As filed with the Securities and Exchange Commission on June 12, 2003
                                                  Registration No. 333 - 61200

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549
                               -------------------

                                 POST-EFFECTIVE
                                 AMENDMENT NO. 4
                                       TO
                                    FORM S-2
                                       ON
                                    FORM S-3
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                               -------------------

                                ESSEX CORPORATION
             (Exact name of registrant as specified in its charter)

 COMMONWEALTH OF VIRGINIA                                          54-0846569
 (State or other jurisdiction of                              (I.R.S. Employer
 incorporation or organization)                          Identification Number)

                               9150 Guilford Road
                            Columbia, Maryland 21046
                                 (301) 939-7000

(Address,  including zip code,  and telephone  number,  including  area
code, of Registrant's principal executive offices)


       Leonard E. Moodispaw                          WITH COPY TO:
   President and Chief Executive                D. Scott Freed, Esquire
              Officer
         Essex Corporation                Whiteford, Taylor & Preston L.L.P.
        9150 Guilford Road                      Seven Saint Paul Street
     Columbia, Maryland 21046                  Baltimore, Maryland 21202
          (301) 939-7000                            (410) 347-8700

 (Name, address, including zip code, and telephone number, including area code,
 of agent for service)

Approximate  date  of  commencement  of  proposed  sale  to  public:  As soon as
practicable after the effective date of this Registration Statement.

         If the only securities  being registered on this form are being offered
pursuant to dividend or interest  reinvestment plans, please check the following
box. / /

         If any of the  securities  being  registered  on  this  form  are to be
offered  on a  delayed  or  continuous  basis  pursuant  to Rule 415  under  the
Securities Act of 1933,  other than  securities  offered only in connection with
dividend or interest reinvestment plans, check the following box. /X/

         If this form is filed to register additional securities for an offering
pursuant to Rule 462(b) under the Securities Act, please check the following box
and list  the  Securities  Act  registration  statement  number  of the  earlier
effective registration statement for the same offering. / /

         If this  form is a  post-effective  amendment  filed  pursuant  to Rule
462(c) under the Securities Act, check the following box and list the Securities
Act  registration   statement  number  of  the  earlier  effective  registration
statement for the same offering. / /

         If delivery of the  prospectus  is expected to be made pursuant to Rule
434, please check the following box. / /


THE REGISTRANT HEREBY AMENDS THIS  REGISTRATION  STATEMENT ON SUCH DATE OR DATES
AS MAY BE NECESSARY TO DELAY ITS EFFECTIVE DATE UNTIL THE REGISTRANT  SHALL FILE
A FURTHER AMENDMENT WHICH SPECIFICALLY  STATES THAT THIS REGISTRATION  STATEMENT
SHALL  THEREAFTER  BECOME  EFFECTIVE  IN  ACCORDANCE  WITH  SECTION  8(a) OF THE
SECURITIES ACT OF 1933, AS AMENDED,  OR UNTIL THE  REGISTRATION  STATEMENT SHALL
BECOME EFFECTIVE ON SUCH DATE AS THE COMMISSION, ACTING PURSUANT TO SAID SECTION
8(a), MAY DETERMINE.






PROSPECTUS                                 SUBJECT TO COMPLETION:  June 12, 2003




                                ESSEX CORPORATION

                         785,000 Shares of Common Stock

         We have prepared this prospectus to allow some of our  stockholders and
         optionholders  to sell up to 785,000 shares of our common stock.  These
         stockholders  may sell  their  shares at prices  which are based on the
         market price of the stock, on United States  exchanges or in negotiated
         transactions.  Essex will not receive any of the proceeds from the sale
         of the  shares  in the  offering  but may  receive  a small  amount  of
         proceeds upon the exercise of options by an optionholder.

         Our Common Stock trades on the American Stock Exchange under the symbol
         "EYW." On June 9,  2003,  the last  reported  sale  price of our common
         stock was $4.50 per share.

                            -------------------------

          INVESTING IN OUR COMMON STOCK INVOLVES A HIGH DEGREE OF RISK.
                     SEE "RISK FACTORS" BEGINNING ON PAGE 7.

                            -------------------------


NEITHER  THE  SECURITIES  AND  EXCHANGE  COMMISSION  NOR  ANY  STATE  SECURITIES
COMMISSION  HAS APPROVED OR  DISAPPROVED  OF THE COMMON STOCK,  OR DETERMINED IF
THIS PROSPECTUS IS TRUTHFUL OR COMPLETE. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.



                     The date of this Prospectus is , 2003.


THE  INFORMATION IN THIS  PROSPECTUS IS NOT COMPLETE AND MAY CHANGE.  WE MAY NOT
SELL THESE  SECURITIES  UNTIL THE  REGISTRATION  STATEMENT FILED WITH THE SEC IS
EFFECTIVE.  THIS  PROSPECTUS IS NOT AN OFFER TO SELL THESE  SECURITIES AND IT IS
NOT SOLICITING AN OFFER TO BUY THESE  SECURITIES IN ANY STATE WHERE THE OFFER OR
SALE IS NOT PERMITTED.





ESSEX HAS NOT AUTHORIZED  ANYONE,  INCLUDING ANY SALESPERSON OR BROKER,  TO GIVE
ORAL OR WRITTEN INFORMATION ABOUT THIS OFFERING,  ESSEX OR THE SHARES COVERED BY
THIS PROSPECTUS THAT IS DIFFERENT FROM THE INFORMATION  INCLUDED OR INCORPORATED
BY REFERENCE IN THIS  PROSPECTUS.  YOU SHOULD NOT ASSUME THAT THE INFORMATION IN
THIS PROSPECTUS,  OR ANY SUPPLEMENT TO THIS PROSPECTUS,  IS ACCURATE AT ANY DATE
OTHER  THAN THE DATE  INDICATED  ON THE  COVER  PAGE OF THIS  PROSPECTUS  OR ANY
SUPPLEMENT TO IT.

                                       2




                       WHERE YOU CAN FIND MORE INFORMATION

         We file annual, quarterly and other reports, proxy statements and other
information  with the SEC. Our SEC filings are  available to the public over the
Internet at the SEC's web site at http://www.sec.gov. You may also read and copy
any document we file at the SEC's public  reference  rooms at 450 Fifth  Street,
N.W., Washington,  D.C., and in New York, New York and Chicago, Illinois. Please
call the SEC at 1-800-732-0330  for further  information on the public reference
rooms.

         For purposes of this  prospectus,  the SEC allows us to "incorporate by
reference"  certain  information we have filed with the SEC, which means that we
are  disclosing  important   information  to  you  by  referring  you  to  other
information  we have filed  with the SEC.  The  information  we  incorporate  by
reference  is  considered  part  of  this   prospectus.   We  specifically   are
incorporating by reference the following documents:

     o    Our Annual  Report on Form 10-KSB for the fiscal  year ended  December
          29, 2002.

     o    Our  Current  Reports  on Form 8-K filed on March 7,  2003,  April 17,
          2003, June 4, 2003 and the Form 8-K/A filed on June [10], 2003.

     o    Our Quarterly Report on Form 10-QSB for the fiscal quarter ended March
          30, 2003.

     o    All  documents  filed by us pursuant to Section  13(a),  13(c),  14 or
          15(d) of the  Securities  Exchange  Act of 1934 after the date of this
          prospectus and before the termination of the offering.

     o    The  description  of our Common Stock in our Form 8-A filed on June 3,
          2003, as it may be amended from time to time.

         We are  delivering  with this  prospectus a copy of the Form 10-KSB and
the Form 10-QSB referred to above. To obtain a copy of other filings at no cost,
you may write or telephone us at the following address:

                               Corporate Secretary
                                ESSEX CORPORATION
                               9150 Guilford Road
                            Columbia, Maryland 21046
                                 (301) 939-7000

          Neither we nor the selling stockholders have authorized anyone else to
provide you with different information.  Neither we nor the selling stockholders
are making an offer of these  securities  in any state  where the state does not
permit an offer.

                                       3



                           FORWARD-LOOKING STATEMENTS

         Some of the statements contained, or incorporated by reference, in this
prospectus  discuss  future  expectations,  contain  projections  of  results of
operations or financial condition or state other "forward-looking"  information.
Those statements are subject to known and unknown risks, uncertainties and other
factors  that could  cause the actual  results to differ  materially  from those
contemplated by the statements.  The  "forward-looking"  information is based on
various factors and was derived using numerous  assumptions.  In some cases, you
can identify these so-called  "forward-looking  statements" by words like "may,"
"will," "should," "expects," "plans,"  "anticipates,"  "believes,"  "estimates,"
"predicts,"  "potential," or "continue" or the negative of those words and other
comparable  words.  You should be aware that those  statements  only reflect our
predictions.  Actual  events or  results  may  differ  substantially.  Important
factors that could cause our actual results to be materially  different from the
forward-looking  statements  are disclosed  under the heading "Risk Factors" and
throughout this prospectus.
                                       4




                                ESSEX CORPORATION

         Based  in  Columbia,   Maryland,   Essex  develops  and  commercializes
optoelectronic  devices for  industry and  government.  In the area of services,
Essex  provides  optoelectronic  and signal  processing  expertise to government
customers  under highly  classified  advanced and next  generation  research and
development  contracts,  supports the  intelligence  community  mission critical
voice and video systems  infrastructure,  and provides highly classified systems
engineering  to  government  customers.  In the area of  products,  Essex builds
optical  communications  and  networking  system  elements and  components.  Our
products  and  services  incorporate  advances  achieved  through  more than two
decades  of  pioneering  work  in  developing  high-throughput   optoelectronics
processors  and receivers for image,  signal and data  processing,  and advanced
communications  applications  for  U.S.  intelligence  organizations.  See  "Our
Products and Services" below for more information about our technology, services
and products under development.

                          SUMMARY FINANCIAL INFORMATION

         The  following  table  contains  summary  information  derived from the
financial statements included in our Annual Report on Form 10-KSB for the fiscal
year ended December 29, 2002 and Quarterly  Report on Form 10-QSB for the fiscal
quarter ended March 30, 2003,  incorporated by reference  herein,  and should be
read in  conjunction  with those  financial  statements  and the  related  notes
thereto.



                                             FISCAL YEAR ENDED

                              DECEMBER 29, 2002            DECEMBER 30, 2001
                         ----------------------       ----------------------

                                                     
Revenues                         $4,506 419                   $2,641,776
Operating loss                   $2,150,159                    3,577,136
Net loss                        ($2,173,617)                  (3,569,199)

                                           FISCAL QUARTER ENDED

                             MARCH 30, 2003 (1)             MARCH 31, 2002
                         -------------------          --------------------

Revenues                        $3,001,334                    $763,276
Operating Loss                  $    4,423                     823,889
Net Loss                       ($   20,081)                   (830,031)

                                            AS OF MARCH 30, 2003

Working capital                                  $     882,687

Total Assets                                     $  7,586,712
Goodwill                                         $  3,014,000 (2)
Stockholders' Equity                             $  4,358,438
Accumulated Deficit                             ($ 14,418,443)



1.       Includes one month of  operations of Sensys  Development  Laboratories,
         Inc.  (SDL),  which  we  acquired  as of  March 1,  2003.  See  "RECENT
         DEVELOPMENTS" below.

2.       Reflects goodwill resulting from our acquisition of SDL.


                                       5





                                  THE OFFERING


Shares of common stock offered by us            None


Shares of common stock that may be              785,000
sold by the selling stockholders


Use of Proceeds                                 We will not receive any proceeds
                                                from the resale of the shares
                                                offered hereby, all of which
                                                proceeds will be paid to the
                                                Selling Stockholders.  We may
                                                receive a small amount of
                                                proceeds if and when an
                                                optionholder exercises the
                                                option that it holds and we will
                                                use those proceeds for general
                                                corporate purposes.


Risk Factors                                    The purchase of our common stock
                                                involves a high degree of risk.
                                                You should carefully review and
                                                consider the disclosure under
                                                "Risk Factors"  beginning on
                                                page 7.


American Stock Exchange Trading Symbol          EYW


                               RECENT DEVELOPMENTS

         Effective March 1, 2003 Essex acquired Sensys Development Laboratories,
Inc.  (SDL),  a  Maryland-based  provider  of systems and  software  engineering
services to the  intelligence  community.  SDL's skill and experience are highly
complementary  to  Essex's  core  competencies  in image and  signal  processing
technology.  The acquisition adds over 25 employees,  an estimated $4 million to
Essex  2003  revenues  and a  solid  base of  contracts  with  excellent  growth
potential.  SDL's revenues were  approximately $3.1 million and $1.1 million for
the fiscal year ended  September 30, 2002 and the fiscal  quarter ended December
31, 2002,  respectively.  Historical  financial  statements of SDL and pro forma
information presenting the effect of the acquisition as if it had been completed
on December 30, 2001 are contained in our Current  Report on Form 8-K filed with
the SEC on April 17, 2003. The Form 8-K is  incorporated  in this  prospectus by
reference.

                                       6




                                  RISK FACTORS

         You  should  carefully  consider  the  following  risk  factors  before
deciding  to invest in our Common  Stock.  You should  also  consider  the other
information  in this  prospectus  and the  additional  information  in our other
reports  on file  with  the  SEC  and in the  other  documents  incorporated  by
reference in this prospectus.  See "Where You Can Find More Information" on page
3.

                     RISKS RELATED TO OUR FINANCIAL RESULTS

WE HAVE A HISTORY OF NET LOSSES AND WE MAY NOT ACHIEVE OR SUSTAIN PROFITABILITY.

         We incurred a net loss for each of our fiscal years ended  December 29,
2002 and December 30, 2001 and for our fiscal  quarter ended March 30, 2003. The
Company also incurred net losses in fiscal 2000 and 1998. In 1999, we reported a
small net income.  As of March 30, 2003, we had an accumulated  deficit of $14.4
million.  Our revenues have  increased  from $2.6 million in fiscal 2001 to $4.5
million in fiscal  2002,  primarily  as a result of higher  revenues  on new and
expanding  U.S.  Government  programs.  In the first fiscal  quarter of 2003 our
revenues were approximately $3.0 million compared to revenues of $763,000 in the
same quarter in 2003,  primarily as a result of expansion of government programs
and the inclusion of one month of results for SDL,  which we acquired  effective
March 1, 2003.  Since  September  2000, we have primarily  funded our operations
from the sale of equity  securities.  We also  expect to incur  significant  but
reduced product  development and related expenses,  and as a result we will need
to increase revenues to achieve profitability.

IF OUR ACTUAL CAPITAL REQUIREMENTS VARY SIGNIFICANTLY FROM OUR EXPECTATIONS,  WE
MAY REQUIRE ADDITIONAL FINANCING SOONER THAN ANTICIPATED.

         Between   September   2000  and  December   2002,   we  have   received
approximately   $6.6  million  from  Private   Investors  to  pursue  commercial
applications  of  our  optical  and  wireless  communications  technologies  and
resulting products.  Receipt of additional funds will be critical to our ability
to continue to develop  our  commercial  technologies  and  products  because we
currently  experience and expect to continue to experience negative or breakeven
cash flows. Our actual capital requirements depend upon several factors that are
difficult  to  predict,  including  the  timing  of  market  acceptance  of  our
commercial  products under development,  our ability to establish and expand our
customer  base  for  our  commercial   products  and  services,   the  level  of
expenditures for sales and marketing and general and  administrative  functions,
the level of revenues from our U.S. Government  contracts,  the cost of offering
additional  services  and  other  factors.  If  our  capital  requirements  vary
materially from those currently  planned,  we may require  additional  financing
sooner than anticipated. The capital raising environment for small-cap companies
like Essex that are developing  communications  technology products has been and
remains in a depressed state.  Even if additional  funding becomes  available it
may be based  on an  unacceptably  low  valuation  for the  Company  and/or  its
technology  assets.  As a result,  we cannot assure you that additional  funding
will be  available  or could  be  obtained  in  sufficient  amounts  or on terms
acceptable  to us, if at all,  or on terms  that would not  include  substantial
dilution to our stockholders. Without timely financing, we would have to curtail
or eliminate development and further reduce expenditures.

                                       7




                          RISKS RELATED TO OUR BUSINESS

WE CURRENTLY  RELY ON SALES TO U.S.  GOVERNMENT  ENTITIES,  AND THE LOSS OF SUCH
CONTRACTS WOULD HAVE A MATERIAL ADVERSE IMPACT ON OUR OPERATING RESULTS.

                  During  fiscal  2002  and  2001,   contracts   with  the  U.S.
Government,  primarily the military  services and other departments and agencies
of the Department of Defense  (DoD),  accounted for  approximately  97%, or $4.4
million of our revenues, and 84%, or $2.2 million of our revenues, respectively.
In the fiscal quarter ended March 30, 2003, revenues on U.S. Government programs
were $2.9 million, or 96.3% of our revenues.

         The loss or  significant  reduction  in  government  funding of a large
program in which we  participate  could  also  materially  adversely  affect our
future  revenues,  earnings  and cash  flows  and thus our  ability  to meet our
financial  obligations.  U.S.  Government  contracts  are  conditioned  upon the
continuing  approval by Congress of the amount of necessary  spending.  Congress
usually  appropriates  funds for a given  program  each  fiscal year even though
contract  periods  of  performance  may exceed  one year.  Consequently,  at the
beginning of a major  program,  the contract is usually  partially  funded,  and
additional monies are normally  committed to the contract only if appropriations
are made by Congress for future fiscal years.

GOVERNMENT CONTRACTS CONTAIN UNFAVORABLE  TERMINATION PROVISIONS AND ARE SUBJECT
TO AUDIT AND MODIFICATION.

         Companies engaged in supplying  defense-related  services and equipment
to U.S.  Government  agencies are subject to certain  business risks peculiar to
the defense industry.  These risks include the ability of the U.S. Government to
unilaterally:

     o    suspend us from receiving new contracts pending  resolution of alleged
          violations of procurement laws or regulations;

     o    terminate existing contracts;

     o    reduce the value of existing contracts;

     o    audit  our  contract-related   costs  and  fees,  including  allocated
          indirect costs; and

     o    control and potentially prohibit the export of our products.

         Any of our U.S.  Government  contracts  can be  terminated  by the U.S.
Government  either  for its  convenience  or if we default by failing to perform
under the contract.  Termination for convenience provisions provide only for our
recovery of costs incurred or committed,  settlement  expenses and profit on the
work completed prior to termination.  Termination for default provisions provide
for the contractor to be liable for excess costs incurred by the U.S. Government
in procuring undelivered items from another source.

OUR FIXED PRICE CONTRACTS MAY COMMIT US TO UNFAVORABLE TERMS.

         We provide  some of our  products  and  services  through  fixed  price
contracts.  Fixed price  contracts  provided 45% and 28% of our sales for fiscal
2001 and 2002, respectively. In a fixed price contract, the price is not subject
to  adjustment  based on cost  incurred to perform the  required  work under the
contract.  Therefore, we fully absorb cost overruns on fixed price contracts and
this

                                       8


reduces our profit margin on the  contract.  Those cost overruns may result in a
loss. A further risk  associated with fixed price contracts is the difficulty of
estimating  sales and costs that are related to performance  in accordance  with
contract  specifications  and the possibility of obsolescence in connection with
long-term procurements. Failure to anticipate technical problems, estimate costs
accurately or control  costs during  performance  of a fixed price  contract may
reduce our profit or cause a loss on the contract.

SINCE WE ARE CURRENTLY  DEVELOPING  OUR OPTICAL AND WIRELESS  TELECOMMUNICATIONS
PRODUCTS IT IS DIFFICULT TO EVALUATE OUR FUTURE BUSINESS AND PROSPECTS.

         We have traditionally derived our revenues from providing  engineering,
communications and signal processing services to the U.S.  Government.  While we
continue to provide  these  services,  over the past year we have  continued  to
emphasize  our  work  on  developing  new   optoelectronics   telecommunications
products,  including  HYPERFINE WDM fiber optic  communications  technology  and
Optical Processor Enhanced Receiver Architecture (OPERA(TM)) technology. Because
our  development  efforts on these  products  are  ongoing and we have not begun
significant commercial sales of these products, our revenue and profit potential
is unproven and our limited history in the commercial  telecommunications  field
makes it difficult to evaluate our business and  prospects.  We have  difficulty
accurately  forecasting our commercial  revenue,  and we have limited historical
financial  data upon  which to base  operating  production  budgets.  You should
consider  our  business  and  prospects  in light of the  heightened  risks  and
unexpected  expenses  and  problems  we may  face as a  company  developing  new
commercial products for a rapidly changing industry.

IF WE DO NOT SUCCESSFULLY  IMPLEMENT OUR PLAN TO EXPAND INTO COMMERCIAL  MARKETS
OUR STOCK PRICE AND VALUATION MAY DECLINE.

         In  addition  to  continuing  to  pursue  our  business  with  the U.S.
Government,  we are focusing our technical capabilities and expertise on related
commercial  markets,  including  HYPERFINE WDM,  OPERA(TM) and ImSyn(TM).  These
products are still under various stages of development.  As such, these products
are subject to certain risks and may require us to:

     o    develop marketing, sales and customer support capabilities;

     o    obtain customer and/or regulatory certification;

     o    respond to rapid technological advances; and

     o    obtain customer acceptance of these products and product performance.

         Our  efforts  to enter  commercial  markets  will  require  significant
resources,  including  additional working capital and capital  expenditures,  as
well as the use of  management's  time.  Our  efforts  to  sell  our  commercial
telecommunications  products,  particularly our optical networking and broadband
wireless communications products, also may depend to a significant degree on the
efforts of independent  distributors or communication service providers.  We can
give no assurance that these  distributors or service  providers will be able to
market our products or their  services  successfully  or that we will be able to
realize  a return  on our  investments  in  them.  If we are not  successful  in
addressing these risks or in developing these commercial business  opportunities
investors that purchased our stock based on the potential  commercial market may
sell their shares and this could cause our stock price and valuation to decline.

                                       9


OUR STRATEGY INVOLVES PURSUING  STRATEGIC  ACQUISITIONS AND INVESTMENTS THAT MAY
NOT BE SUCCESSFUL.

         Our  business   strategy   includes   acquiring  or  making   strategic
investments  in  other  companies  with a view to  expanding  our  portfolio  of
products  and  services,  acquiring  new  technologies,   and  accelerating  the
development  of new or  improved  products.  To do so, we may issue  equity that
would dilute our current  shareholders'  percentage ownership or incur or assume
indebtedness.  In  addition,  we may  incur  significant  amortization  expenses
related  to  intangible  assets.  We also may incur  significant  write-offs  of
goodwill associated with companies,  businesses or technologies that we acquire.
Acquisitions and strategic investments involve numerous risks, including:

     o    difficulties in integrating the operations, technologies, and products
          of the acquired companies;

     o    diversion of management's attention from our core business;

     o    potential difficulties in completing projects of the acquired company;

     o    the potential loss of key employees of the acquired company; and

     o    dependence on unfamiliar or relatively small supply partners.

         In addition,  acquisitions and strategic  investments may involve risks
of  entering  markets in which we have no or limited  direct  prior  experience,
where  competitors  in  such  markets  have  stronger  market  positions  and of
obtaining  insufficient  revenues to offset increased  expenses  associated with
acquisitions.

OUR SUCCESS LARGELY DEPENDS ON OUR ABILITY TO RETAIN KEY PERSONNEL.

         Our success has always depended in large part on our ability to attract
and retain highly-skilled technical,  managerial, sales and marketing personnel,
particularly  those  skilled  and  experienced  in  optoelectronics  and optical
communications  equipment.  The  loss  of key  personnel  may  prevent  us  from
completing current development and restrict new development.

IF WE ARE UNABLE TO DEVELOP AND SUCCESSFULLY INTRODUCE NEW AND ENHANCED PRODUCTS
THAT  MEET THE NEEDS OF OUR  CUSTOMERS  IN A TIMELY  MANNER,  OUR  REVENUES  AND
RESULTS OF OPERATIONS COULD BE ADVERSELY AFFECTED.

         Our future success  depends on our ability to anticipate our customers'
needs and develop products that address those needs. Technological change in the
optical networking industry is occurring at a rapid pace. As a result, we expect
there to be frequent new product introductions, changes in customer requirements
and evolving industry  standards.  We may not be able to develop new products or
enhancements to our existing  products in a timely manner, or at all. This would
cause  potential  customers  to seek other  solutions,  which  would  reduce our
revenues and adversely affect our results of operations and financial condition.

         We are currently  developing many potential optical networking products
through our research and development efforts.  Although we have several products
in development, we may not bring all of these potential products into commercial
production due to:

     o    changes in customer demand;

                                       10



     o    technological developments that make our products less competitive;

     o    evolving industry standards; or

     o    allocation of our limited resources to other products or technologies.

         If we incur  significant  expenses  developing  products that we do not
produce  commercially,  or if we select the wrong  products or  technologies  to
bring into commercial  production,  our revenues and results of operations could
be  adversely  affected  and  we  may  not  recover  significant   research  and
development expenses.

ONE ASPECT OF OUR SUCCESS IS DEPENDENT ON OUR OPTOELECTRONICS TELECOMMUNICATIONS
PRODUCTS BEING  DEVELOPED.  FAILURE OF OUR PRODUCTS TO OPERATE AS EXPECTED COULD
DELAY OR  PREVENT  THEIR  DEPLOYMENT  AND SALE AND COULD  SERIOUSLY  IMPAIR  OUR
COMMERCIAL BUSINESS AND PROSPECTS.

         Our future growth and success depends in part on the commercial success
of our optical and wireless telecommunications products being developed. We have
begun limited commercial sales of our products and have produced devices only to
specifications  required in order to conduct  laboratory tests and field trials.
Some of our devices have been deployed in field trials,  others have been tested
in our  laboratories  and still others are in earlier stages of development.  If
our  products  fail to operate as  expected,  this could delay or prevent  their
deployment and sale and could seriously impair our business and prospects.

THE  MARKET WE INTEND TO SERVE IS HIGHLY  COMPETITIVE  AND WE MAY NOT BE ABLE TO
ACHIEVE OR MAINTAIN PROFITABILITY.

         Competition in the network communications  equipment market is intense.
This market has historically  been dominated by such large companies as Alcatel,
Ciena,  Cisco  Systems,  JDS  Uniphase,  Lucent  Technologies,  NEC  and  Nortel
Networks. Some of these companies, as well as emerging companies,  are currently
developing  products  that may  compete  in the  specialty  areas  that  Essex's
technology  is  designed to address.  We may face  competition  from other large
communications  companies  who may enter  our  proposed  markets.  Many of these
possible competitors have longer operating histories,  greater name recognition,
larger customer bases and greater  financial,  technical and sales and marketing
resources  than  we do and may be able to  undertake  more  extensive  marketing
efforts  and adopt more  aggressive  pricing  policies  than we can.  Due to the
rapidly  evolving  markets  in which we  compete,  additional  competitors  with
significant  market  presence  and  financial  resources  may enter our markets,
further intensifying competition.

IF WE ARE UNABLE TO PROTECT OUR  INTELLECTUAL  PROPERTY  EFFECTIVELY,  WE MAY BE
UNABLE TO PREVENT THIRD PARTIES FROM USING OUR TECHNOLOGIES,  WHICH WOULD IMPAIR
OUR COMPETITIVE ADVANTAGE.

         We rely on a  combination  of patent,  copyright,  trademark  and trade
secret laws and restrictions on disclosure to protect our intellectual  property
rights. We also enter into  confidentiality  or license  agreements with our key
employees  and  consultants  and  control  access  to  and  distribution  of our
software,  documentation and other proprietary information. The Company believes
that  its  patents  and  patent  applications  provide  it  with  a  competitive
advantage.  Accordingly,  in the event the Company's  products and  technologies
under development gain market  acceptance,  patent protection would be important
to the Company's  business.  However,  obtaining  patent and other  intellectual
property  protection may not adequately  protect our rights or permit us

                                       11




to gain or keep any competitive  advantage.  For instance,  unauthorized parties
may attempt to copy,  reverse  engineer or otherwise obtain and use our patented
products or technology  without our permission,  thus eroding or eliminating the
competitive  advantage we hope to gain though the exclusive  rights  provided by
patent  protection.  Moreover,  our existing patents and patents we have applied
for (if  granted)  may not  protect us against  competitors  that  independently
develop proprietary  technologies that are substantially  equivalent or superior
to our technologies,  or design around our patents. In addition, the competitive
advantage  provided by patenting our  technology may erode if we do not upgrade,
enhance and  improve  our  technology  on an ongoing  basis to meet  competitive
challenges.

         Monitoring  unauthorized  use of our  technology is  difficult,  and we
cannot be certain that the steps we have taken will prevent  unauthorized use of
our technology, particularly in foreign countries where the laws may not protect
our proprietary rights as fully as in the United States. A complete  description
of Essex's patents and patent  applications is contained in our Annual Report on
Form 10-KSB for fiscal 2002. The Form 10-KSB is  incorporated in this prospectus
by  reference  and we are  delivering  a copy of the report  together  with this
prospectus.

THERE IS A RISK THAT OUR PATENT APPLICATIONS WILL NOT BE GRANTED.

         Although we have filed several  applications  for U.S. patents relating
to our HYPERFINE WDM and  OPERA(TM)  technologies,  there is a risk that some or
all of our pending  applications will not issue as patents.  Although we believe
our patent  applications are valid,  the failure of our pending  applications to
issue as patents  would  affect  the  competitive  advantage  we hope to gain by
obtaining patent protection and thus likely would have a material adverse effect
upon our business and results of operations.

WE MAY BECOME INVOLVED IN INTELLECTUAL PROPERTY DISPUTES, WHICH COULD SUBJECT US
TO  SIGNIFICANT  LIABILITY,  DIVERT THE TIME AND ATTENTION OF OUR MANAGEMENT AND
PREVENT US FROM SELLING OUR PRODUCTS.

         We or our  customers  may be a party to  litigation  in the  future  to
protect our intellectual  property or to respond to allegations that we infringe
on others'  intellectual  property.  Any  parties  asserting  that our  products
infringe upon their  proprietary  rights would force us to defend  ourselves and
possibly our customers against the alleged infringement.  If we are unsuccessful
in any  intellectual  property  litigation,  we could be subject to  significant
liability for damages and loss of our proprietary rights.  Intellectual property
litigation,  regardless  of its  success,  would  likely be time  consuming  and
expensive  to resolve  and would  divert  management's  time and  attention.  In
addition, we could be forced to do one or more of the following:

     o    stop  selling,  incorporating  or using our products  that include the
          challenged intellectual property;

     o    obtain from the owner of the infringed  intellectual  property right a
          license to sell or use the relevant technology,  which license may not
          be available on reasonable terms, or at all; or

     o    redesign those products that use the technology.

         If we are forced to take any of these  actions,  our business  could be
seriously harmed.

                                       12


IF NECESSARY  LICENSES OF THIRD-PARTY  TECHNOLOGY ARE NOT AVAILABLE TO US OR ARE
VERY EXPENSIVE, OUR BUSINESS WOULD BE SERIOUSLY HARMED.

         From time to time we may be required to license  technology  from third
parties  to sell  or  develop  our  products  and  product  enhancements.  These
third-party  licenses  may not be  available  to us on  commercially  reasonable
terms,  if at all. Our inability to maintain or obtain any  third-party  license
required to sell or develop our products and product  enhancements could require
us to obtain substitute  technology of lower quality or performance standards or
at greater cost. If we were required to use  technology  with lower  performance
standards  or quality,  customers  may stop buying our  products  and this would
cause our  revenues  to  decline.  Similarly,  if our costs rise  significantly,
customers may choose less expensive alternative products,  which would cause our
revenues to decline.

                RISKS RELATED TO THE OPTICAL NETWORKING INDUSTRY

THE OPTICAL NETWORKING  INDUSTRY IS DEVELOPING,  UNPREDICTABLE AND CHARACTERIZED
BY RAPID TECHNOLOGICAL CHANGES AND EVOLVING STANDARDS. IF THIS INDUSTRY DOES NOT
DEVELOP AND EXPAND AS WE ANTICIPATE, DEMAND FOR OUR PRODUCTS MAY FAIL TO GROW OR
MAY DECLINE, WHICH WOULD ADVERSELY AFFECT OUR REVENUES.

         The optical  networking  industry is developing  and  characterized  by
rapid  technological  change,  frequent  new product  introductions,  changes in
customer requirements and continuously evolving industry standards. As a result,
it is  difficult  to predict  its  potential  size and future  growth  rate.  In
addition,  evolving customer  requirements and industry standards are uncertain.
Our success in generating  revenues in this  evolving  market will depend on our
ability to:

     o    establish,   maintain  and  enhance  our  relationships  with  optical
          networking customers;

     o    convince  our  customers of the  benefits of  next-generation  optical
          networks; and

     o    predict  accurately,  and  develop  our  products  to  meet,  evolving
          customer requirements and industry standards.

         If we fail to address changing market conditions, sales of our products
may fail to grow or may decline, which would adversely affect our revenues.

THE OPTICAL  NETWORKING  EQUIPMENT  INDUSTRY IS EXPERIENCING  DECLINING  AVERAGE
SELLING PRICES, WHICH COULD ADVERSELY AFFECT OUR REVENUES AND GROSS MARGINS.

         The optical  networking  equipment  industry is experiencing  declining
average  selling prices as a result of increasing  competition  and greater unit
volumes as  communications  service  providers  continue  to deploy  fiber optic
networks. We anticipate that average selling prices will continue to decrease in
the future in response to product introductions by competitors,  price pressures
from significant customers and greater manufacturing efficiencies. These average
selling price declines may  contribute to a decline in our gross margins,  which
could adversely affect our results of operations.

                                       13


IF THE  INTERNET  AND  COMMERCIAL  DATA  NETWORKS DO NOT  CONTINUE TO EXPAND AND
NEXT-GENERATION  OPTICAL  NETWORKS ARE NOT DEPLOYED AS RAPIDLY AS WE ANTICIPATE,
SALES OF OUR PRODUCTS  UNDER  DEVELOPMENT  MAY DECLINE,  AND OUR REVENUES MAY BE
ADVERSELY AFFECTED.

         Our future  commercial  success depends on the continued  growth of the
Internet and  commercial  data  networks for  commerce and  communications,  the
continuing  increase  in the  amount  of data  transmitted  over  communications
networks and the increasing  adoption of, and  improvements to, optical networks
to meet the increased  demand for  bandwidth.  If data  networks,  including the
Internet,  do not continue to expand as a widespread  communications  medium and
commercial  marketplace,  the need for significantly  increased bandwidth across
networks  and the market for optical  networking  products  may not  continue to
develop.  Future demand for the products we are developing is uncertain and will
depend to a great  degree on the  continued  growth  and  upgrading  of  optical
networks.

BECAUSE OPTICAL  PRODUCTS ARE COMPLEX AND ARE DEPLOYED IN COMPLEX  ENVIRONMENTS,
THE PRODUCTS WE ARE DEVELOPING MAY HAVE DEFECTS THAT WE DISCOVER ONLY AFTER FULL
DEPLOYMENT, WHICH COULD SERIOUSLY HARM OUR BUSINESS.

         Optical  products  are complex and are designed to be deployed in large
quantities across complex networks.  Because of the nature of the products, they
can only be fully tested when  completely  deployed in large  networks with high
amounts of traffic.  Customers may discover errors or defects in the hardware or
the  software,  or products we develop may not operate as  expected,  after they
have been fully deployed. If we are unable to fix defects or other problems that
may be identified in full deployment, we would likely experience:

     o    loss of, or delay in, revenue and loss of market share;

     o    loss of existing customers;

     o    difficulties   in  attracting   new  customers  or  achieving   market
          acceptance;

     o    diversion of development resources;

     o    increased service and warranty costs;

     o    legal actions by our customers; and

     o    increased insurance costs.

         The  occurrence  of any of  these  problems  could  seriously  harm our
business,  financial condition and results of operations.  Defects,  integration
issues or other performance  problems could result in financial or other damages
to our customers or could negatively  affect market  acceptance for the products
we develop.  Our customers could also seek damages for losses from us, which, if
they were successful, would seriously harm our business, financial condition and
results of operations.  A product  liability  claim brought  against us, even if
unsuccessful,  would likely be time  consuming and costly and would put a strain
on our management and resources.

                                       14




                         RISKS RELATED TO THIS OFFERING

A LIMITED NUMBER OF STOCKHOLDERS  ARE ABLE TO EXERT  SIGNIFICANT  INFLUENCE OVER
MATTERS REQUIRING STOCKHOLDER APPROVAL.

         Since  September  2000,  the  Company  has  engaged in several  private
placements with a few private investors or their  affiliates.  We refer to these
entities and their affiliates as the "Private Investors". As of the date of this
prospectus,  these Private Investors hold collectively approximately 3.6 million
shares of common stock, including 660,000 shares of Common Stock covered by this
Prospectus.  The Private Investors also hold warrants  exercisable under certain
circumstances for up to two million shares of our common stock. Accordingly, the
Private  Investors could seek to exercise  significant  control and influence of
certain  actions  requiring  the approval of the holders of shares of our common
stock.  This  concentration  of ownership  may also delay or prevent a change in
control of Essex or reduce the price other investors might be willing to pay for
our common  stock.  In  addition,  the  interests of the Private  Investors  may
conflict with the interests of other holders of our common stock.

THERE IS  CURRENTLY  ONLY A LIMITED  PUBLIC  MARKET FOR OUR COMMON STOCK AND OUR
COMMON STOCK IS SUBJECT TO SIGNIFICANT PRICE fluctuations.

         Our common stock has recently been included for listing on the American
Stock Exchange (AMEX). Prior to the AMEX listing, our common stock was traded on
the OTC  Bulletin  Board.  Historically,  there has been  only a limited  public
market  for our  common  stock and we do not  expect  that an active  and robust
trading  market to develop until the number of shares in the hands of the public
is substantially increased. In addition, in the event our operating results fall
below the expectations of public market analysts and investors, the market price
of our common stock would likely be materially adversely affected.

         The  trading  price of our common  stock is likely to be  volatile  and
sporadic.  The stock market in general,  and the market for technology companies
in particular,  has experienced  extreme  volatility.  This volatility has often
been unrelated to the operating performance of particular companies.  Volatility
in the market price of our common stock may prevent investors from being able to
sell  their  common  stock at or above the price such  investors  paid for their
shares or at any price at all.

SALES BY THE SELLING STOCKHOLDERS OR OTHERS OF A SIGNIFICANT NUMBER OF SHARES OF
COMMON STOCK COULD HAVE A MATERIAL ADVERSE EFFECT ON PREVAILING MARKET PRICES.

         We cannot predict what effect,  if any, that future sales of shares, or
the availability of shares for future sale, will have on the market price of our
common stock  prevailing from time to time.  Nevertheless,  sales of substantial
amounts of common stock by the selling stockholders, or the perception that such
sales may occur,  could  have a material  adverse  effect on  prevailing  market
prices.

         At March 31, 2003, we have outstanding approximately 8.9 million shares
of our common stock,  approximately 4,348,000 of which were sold or issued by us
in private  transactions in reliance upon exemptions from registration under the
Securities Act. (See "Other Business  Information - Recent  Developments" in our
2002 Form 10-KSB for further  information.) These privately placed shares may be
sold only pursuant to an effective  registration  statement filed by

                                       15


Essex or an applicable exemption,  including the exemption contained in Rule 144
promulgated under the Securities Act. In general, under Rule 144 as currently in
effect,  a  shareholder,  including an  affiliate  of Essex,  may sell shares of
common stock after at least one year has elapsed since such shares were acquired
from us or an affiliate of ours.  The number of shares of common stock which may
be sold within any three-  month period is limited to the greater of one percent
of the then  outstanding  number of shares of common stock or the average weekly
trading volume in the common stock during the four calendar weeks  preceding the
date on which  notice of such  sale was filed  under  Rule  144.  Certain  other
requirements of Rule 144 concerning  availability of public information,  manner
of sale and notice of sale must also be  satisfied.  In addition,  a shareholder
who is not our  affiliate  (and who has not been our affiliate for 90 days prior
to the sale)  and who has  beneficially  owned  shares  acquired  from us or our
affiliate for over two years may resell the shares without  compliance  with the
foregoing requirements under Rule 144.

         In  addition  to the shares  covered by this  prospectus,  the  Private
Investors  have been  granted  rights to have up to  2,000,000  shares of common
stock issuable upon exercise of warrants  registerable  under the Securities Act
upon demand and another  approximately  600,000  shares of common stock  through
"piggy-back" registration rights. We have also filed a registration statement to
register an additional 1.17 million shares held by the Private Investors and 1.l
million  shares held by other parties.  Sales of  substantial  amounts of common
stock under Rule 144 or pursuant to the  holder's  registration  rights,  or the
perception  that such sales may occur,  could have a material  adverse effect on
prevailing market prices.

WE ARE AT RISK OF SECURITIES  CLASS ACTION  LITIGATION DUE TO OUR EXPECTED STOCK
PRICE VOLATILITY.

         In the past,  securities class action litigation has often been brought
against  companies  after  periods of  volatility  in the market  price of their
securities.  Securities  litigation could result in substantial costs and divert
management's  attention  and resources  from our business.  Due to the potential
volatility of our stock price, we may be the target of securities  litigation in
the future.

                            OUR PRODUCTS AND SERVICES

         Capitalizing  on our expertise  and success in developing  and building
optoelectronic systems for national security applications, we has developed five
core areas of technological expertise and intellectual property:

     1)   Optoelectronic  processors  and  processing  (including  the  Advanced
          Optical  Processor  (AOP)  program  and  Optical  Processor   Enhanced
          Receiver Architecture (OPERA(TM)) technology);

     2)   HYPERFINE  WAVELENGTH  DIVISION   MULTIPLEXING  (WDM)  technology  for
          telecommunications;

     3)   Communications  services  (including  the  capabilities  of the  newly
          formed Communications Services Division);

     4)   Signal  processing  (including the  capabilities of recently  acquired
          Sensys Development Laboratories, Inc.); and

                                       16



     5)   Virtual    Lens    Imaging    (VLI)    technology    (including    the
          ImSyn(TM)processor   and  technology,   for  above  and  below  ground
          imaging).

         Our services and products for sale and under development include:

     o    The Advanced  Optical  Processor  (AOP) being developed by Essex under
          contract for the United States Missile Defense Agency (MDA) is a third
          generation  device which leverages  spread  spectrum signal  analysis,
          wideband ELINT (electronic intelligence) and cryptologic exploitation.
          The AOP is used for ballistic missile defense  environments.  In these
          environments,  not only must the missile  target be  identified  using
          Range-Doppler  Imaging  (RDI),  but other items that are sent into the
          threat  environment  to make it  harder to  identify  and  "kill"  the
          missile  target must also be  identified.  Other items  launched along
          with the  missile  include  chaff,  debris,  closely  spaced  objects,
          jammers,  spoofers and missile decoys.  The AOP is a high  performance
          radar signal processor that provides the true correlation-based  image
          formation for ballistic missile defense in a cost-effective, low size,
          low weight and low power package. Separately,  OPERA(TM), an optically
          enhanced  digital signal  processing  technology,  has demonstrated in
          laboratory  modeling a dramatic increase in the quality of service and
          carrying  capacity  for  CDMA  wireless   telecommunications  systems.
          Further  development  and  testing of  OPERA(TM)has  been  temporarily
          delayed  until  funding is  identified  and  obtained to finance  such
          activity.

     o    An  all-optical,  all-passive  technique,  HYPERFINE  WDM fiber  optic
          communications  technology,  which has shown to significantly increase
          the number of channels and their combined bandwidth used for DWDM. The
          core HYPERFINE WDM technology provides:

          -    All passive optical components;

          -    Simple  and  small   packaging,   using  standard   manufacturing
               processes;

          -    Excellent channel isolation;

          -    High density--50 MHz to 100 GHz spacing;

          -    Superior  response and flat filter shapes with excellent  channel
               isolation;

          -    Passband shapes that can be tailored for each application;

          -    Low insertion loss;

          -    Low temperature sensitivity; and

          -    Fixed or tunable designs.

     o    In late 2002 Essex received a telecommunication services contract with
          a potential total  multiyear  contract value of $30 million and formed
          the    Communications    Services    Division    (CSD)   to    provide
          telecommunication  systems  support  in  the  area  of  modernization,
          project management, integration and engineering analysis. The CSD will
          focus on  supporting  the  intelligence  community's  mission-critical
          voice and video systems and associated infrastructure.

     o    Essex has  acquired  SDL, a  Maryland-based  provider  of systems  and
          software  engineering  services to the intelligence  community.  SDL's
          skill  and  experience  are

                                       17


          highly complementary to Essex's  core competencies in image and signal
          processing technology.

     o    The   Virtual   Lens   Imaging   technology   (VLI)   is  a   patented
          high-resolution  imaging system that leverages  Essex's  experience in
          synthetic aperture imagery and optoelectronic system development.  The
          Company's  VLI  technology  is  based  on  the  key  features  of  its
          optoelectronic  processor  and its  ability to  calculate  images from
          non-uniform   data   in  real   time.   Separately,   our   high-speed
          optoelectronic   processor,   Image   Synthesis   (ImSynTM),   enables
          extraordinarily  fast  processing  of data for  complex  visual  image
          systems  including radar imaging,  magnetic  resonance  imaging (MRI),
          microscopy  and  ultrawideband  signal  processing.  We are  currently
          seeking  additional  funding to further the development and testing of
          second generation ImSyn(TM) processors in 2003.

         Essex currently does not have sufficient  resources to bring all of its
telecommunications   and   optoelectronics   processing   devices   to   market.
Accordingly,  Essex will  likely  have to partner  with or enter into  licensing
arrangements with major industry participants in order to successfully introduce
in large  volume its  technology  and  products.  In addition,  several  optical
telecommunications and fiber optic companies, both established and emerging, are
currently  developing  products  that may  compete in the  specialty  areas that
Essex's  technology is designed to address.  Most of these  companies are larger
and  more  established   than  Essex  and  have  existing   customer  bases  and
significantly  greater  access  to  capital  resources  than  Essex.  See  "RISK
FACTORS."

                                 USE OF PROCEEDS

         We will not receive any  proceeds  from the sale of the Common Stock by
the selling stockholders.  We will receive aggregate proceeds of $148,350 if and
when all optionholders fully exercise the options that they hold and we will use
those proceeds for general corporate purposes.

                                       18




                              SELLING STOCKHOLDERS

         This  prospectus  relates  to  the  offering  by the  stockholders  and
optionholders  named in the  prospectus  for resale of up to  785,000  shares of
common stock. Throughout this prospectus, we may refer to these stockholders and
optionholders  and their pledgees,  donees,  transferees or other  successors in
interest  who  receive  shares  in  non-sale   transactions,   as  the  "selling
stockholders."  If they sell all of these shares in this  offering,  the selling
stockholders  will  beneficially  own the  shares of our  Common  Stock as shown
below.

         The following table sets forth the following  information  with respect
to each selling  stockholder  as of March 31,  2003:  (i) name and nature of any
position or other  relationship  with us within the past three  years;  (ii) the
number and  percentage  of total  outstanding  shares of our  Common  Stock each
selling stockholder  beneficially owns before this offering; (iii) the number of
shares of Common Stock the selling stockholder is offering;  and (iv) the number
and percentage of total outstanding  shares of our Common Stock that the selling
stockholder  will own after the selling  stockholder  sells all of the shares in
this offering.

         The table below has been revised to reflect the  following  events that
occurred prior to March 31, 2003: (i) the automatic conversion of 500,000 shares
of Preferred Stock formerly held by certain selling stockholders into a total of
2,000,000  shares of Common Stock;  (ii) the expiration of a voting agreement by
and among GEF Optical Investment  Company,  Inc. and Networking Ventures LLC and
certain affiliated parties; (iii) the dissolution of Networking Ventures LLC and
the removal of Networking  Ventures LLC as a selling  stockholder;  and (iv) the
inclusion of the John G. Hannon as successor to Networking Ventures as a selling
stockholder herein.



                                                                                                      Percentage of
                                               Percentage of                                           Outstanding
                           Amount and           Outstanding                          Amount and         Shares of
                            Nature of            Shares of                           Nature of         Common Stock
                           Beneficial          Common Stock         Shares of        Beneficial        Beneficially
 Name and Address           Ownership          Beneficially          Common          Ownership         Owned After
of Beneficial Owner        Before the          Owned Before           Stock          After the         the Offering
                            Offering           the Offering          Offered          Offering
---------------------    -----------------    -----------------    -----------     ---------------    ---------------

GEF Optical Investment
                                                                                     
   Company, LLC ("GEF")(1)  1,531,532               17.2            330,000          1,210,532            13.5

John G. Hannon (2)          1,538,973               17.3            330,000          1,208,973            13.6
Nottingham Investment
   Company (3)                125,000                1.7            125,000                  0             0.0
---------------------------------


     (1) Includes  118,200  shares held by Global  Environmental  Capital,  LLC.
         ("GECC")  and  166,666  shares  held by  Global  Environment  Strategic
         Technology Partners, LLC ("GESTP"). H. Jeffrey Leonard, the Chairman of
         the Board of Essex,  is a director of the managing member of GEF. Marie
         S.  Minton,  a director of Essex,  is also a director  of the  managing
         member of GEF.  The Company has been  advised  that each of GEF,  GECC,
         GESTP, Mr. Leonard and Ms. Minton may be deemed the beneficial owner of
         all the  shares of common  stock  beneficially  owned by GEF,  GECC and
         GESTP.

(2)      Includes  1,346,666  shares of common stock directly held by the Hannon
         Family LLC over which Mr. Hannon has sole voting and investment  power.
         Also  consists  of  192,307   shares  of  Common  Stock  issuable  upon
         conversion of $500,000  convertible  promissory note held by the Hannon
         Family LLC. John G. Hannon is a director of Essex.

     (3) Total shares beneficially owned prior to the Offering.  As of March 31,
         2003,  Nottingham  Investment Company beneficially owned 115,000 shares
         consisting of options  exercisable  for 115,000 shares of Common Stock.
         Nottingham Investment Company is a Maryland corporation



                                       19




..
                              PLAN OF DISTRIBUTION

         The Common Stock being offered by the selling  stockholders may be sold
in transactions on the OTC Bulletin Board, on another market on which the Common
Stock may be trading, or in privately-negotiated transactions. The sale price to
the public  may be the  market  price  prevailing  at the time of sale,  a price
related  to  the  prevailing  market  price  or  any  other  price  the  selling
stockholders may determine. The Common Stock may also be sold under SEC Rule 144
and not under this prospectus.  The selling stockholders have the discretion not
to accept any  purchase  offer or make any sale of Common Stock if they deem the
purchase price to be unsatisfactory at any particular time, or for any reason.

         The selling  stockholders  may also sell the Common  Stock  directly to
broker-dealers  acting as principals and/or to  broker-dealers  acting as agents
for  themselves  or their  customers.  Brokers  acting as agents for the selling
stockholders  will  receive  usual  and  customary   commissions  for  brokerage
transactions,  and broker-dealers  acting as principals will do so for their own
account at  negotiated  prices and at their own risk.  It is  possible  that the
selling stockholders will sell shares of Common Stock to broker-dealers or other
purchasers  at a price per share  which may be below the then market  price.  In
addition,  the selling  stockholders  may enter into hedging  transactions  with
broker-dealers  who may engage in short  sales of Common  Stock in the course of
hedging  the  positions  they  assume  with a selling  stockholder.  The selling
stockholders  also may sell  shares  short and  deliver  the shares to close out
their positions,  and may loan or pledge their shares to a broker-dealer who may
have the right to sell the loaned or pledged shares on default or otherwise. The
selling stockholders and any brokers, dealers or agents, upon effecting the sale
of any of the Common Stock offered hereby, may be deemed  "underwriters" as that
term is defined under the  Securities  Act or the Exchange Act, or the rules and
regulations thereunder.

         The selling  stockholders  and any other persons  participating  in the
sale  or  distribution  of the  Common  Stock  will  be  subject  to  applicable
provisions  of the Exchange Act and its rules and  regulations,  which may limit
the  timing of  purchases  and sales of any of the Common  Stock by the  selling
stockholders or other distribution participants.  Furthermore,  under Regulation
M,  persons  engaged  in  a  distribution  of  securities  are  prohibited  from
simultaneously  engaging in market making and other  activities  with respect to
such  securities  for a  specified  period of time  before the  commencement  of
distributions subject to specified exceptions or exemptions. This may affect the
marketability of the Common Stock.

         We have agreed to  indemnify  the  selling  stockholders  against  some
important  liabilities,  including  liabilities  under the Securities Act, or to
contribute to any payments these selling stockholders may be required to make in
respect of these  liabilities.  We are paying the costs of this registration for
the selling stockholders.

                                       20




                                  LEGAL MATTERS

         The legal  issuance  and fully  paid and  non-assessable  status of our
Common  Stock  offered by this  prospectus  was passed  upon for us by our legal
counsel,  Whiteford,  Taylor & Preston L.L.P.,  Baltimore,  Maryland.  Counsel's
opinion is included as exhibit 5.1 to the  registration  statement of which this
prospectus is a part.

                                     EXPERTS

         The financial  statements  incorporated in this prospectus by reference
to our Annual  Report on Form 10-KSB for the year ended  December  29, 2002 have
been so incorporated in reliance on the report of Stegman & Company, independent
accountants,  given on the  authority  of said firm as experts in  auditing  and
accounting.

         The historical financial statements of SDL as of September 30, 2002 and
for each of the two years in the period ended September 30, 2002 incorporated in
this  prospectus  by reference to our Current  Report on Form 8-K filed on April
17, 2003,  as amended by the Form 8-K/A filed on June [10],  2003,  have been so
incorporated  in  reliance  on the  report  of  Stegman &  Company,  independent
accountants,  given on the  authority  of said firm as experts in  auditing  and
accounting.


                                       21





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                                TABLE OF CONTENTS

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                                                                       PAGE
                                                                     --------

    Where You Can Find More
      Information.........................................................   3
    Forward Looking Statements.............................................  4
    Essex Corporation......................................................  5
    Summary Financial Information..........................................  5
    The Offering...........................................................  6
    Recent Developments....................................................  6
    Risk Factors...........................................................  7
    Our Products and Services.............................................. 16
    Use of Proceeds........................................................ 18
    Selling Stockholders................................................... 19
    Plan of Distribution................................................... 20
    Legal Matters.......................................................... 21
    Experts................................................................ 21


             ------------------------------------------------------
             ------------------------------------------------------


                                ESSEX CORPORATION

                                  Common Stock
                            ------------------------
                                   PROSPECTUS
                            ------------------------
                                     , 2003

             ------------------------------------------------------
             ------------------------------------------------------

                                     


                                      II-1


                                     PART II

                     INFORMATION NOT REQUIRED IN PROSPECTUS

ITEM 14.  OTHER EXPENSES OF ISSUANCE AND DISTRIBUTION.

         The following table sets forth the fees and expenses in connection with
the issuance and distribution of the securities being registered. Except for the
SEC registration fee, all amounts are estimates.





                                                         
SEC registration fee......................................  $         854
Accounting fees and expenses..............................          4,000
Legal fees and expenses...................................         12,500
Blue Sky fees and expenses (including counsel fees).......          2,500
Printing expenses.........................................            500
Transfer agent's and registrar's fees and expenses........            500
Miscellaneous expenses....................................            200
                                                            --------------

  Total...................................................  $      21,054

                                                            ==============


ITEM 15.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

         The Virginia Stock Corporation Act ("Act") permits  indemnification  of
directors and officers of a corporation under certain  conditions and subject to
certain  limitations.  Articles (h) and (i) of Essex's Articles of Incorporation
contain  provisions for the  indemnification  of directors and officers of Essex
within the limitations permitted by the Act. In addition, Essex has entered into
indemnity  agreements  with all of its directors and officers  which provide the
maximum indemnification allowed by the Act.

ITEM 16.  EXHIBITS AND FINANCIAL STATEMENT SCHEDULES.

     (a) Exhibits:

EXHIBIT
NUMBER       DESCRIPTION

4.1          Specimen Stock Certificate*
5.1          Opinion of Whiteford, Taylor & Preston L.L.P.*
23.1         Consent of Independent Accountants
23.2         Consent of Independent Accountants
23.3         Consent of Whiteford, Taylor & Preston L.L.P. (included in Exhibit
             5.1)*
24           Power of Attorney*
99.1         Securities Purchase Agreement dated March 15, 2001*

                                      II-1


99.2         Amendment No. 2 to Registration Rights Agreement dated March 15,
             2001*
99.3         Securities Purchase Agreement dated December 4,  2000*
99.4         Amendment No. 1 to Registration Rights Agreement dated December 4,
             2000*
99.5         Amendment to Securities Purchase Agreement, dated as of March 1,
             2002, between Essex Corporation and the Hannon Family LLC*
99.6         Amendment to Securities Purchase Agreement, dated as of March 1,
             2002, between Essex Corporation and Global Environment Strategic
             Technology Partners, L.P.*
99.7         Convertible Promissory Note Purchase Agreement by and between Essex
             Corporation and the Hannon Family LLC dated December 17, 2002*
99.8         Convertible Promissory Note dated December 17, 2002 issued by Essex
             Corporation to the Hannon Family LLC*

-----------------------
*    Previously filed

     (b) Financial Statement Schedules.

         None.

ITEM 17.  UNDERTAKINGS.

         (a) The undersigned Registrant hereby undertakes:

                  (1) To file,  during any  period in which  offers or sales are
                  being made, a  post-effective  amendment to this  registration
                  statement:

                           (i) To include  any  prospectus  required  by Section
                  10(a)(3) of the Securities Act of 1933.

                           (ii) To reflect in the prospectus any facts or events
                  arising after the effective date of the registration statement
                  (or  the  most   recent   post-effective   amendment   to  the
                  registration  statement)  which,  individually  or when viewed
                  together,  represent a fundamental  change in the  information
                  set forth in the registration  statement.  Notwithstanding the
                  foregoing,  any  increase or decrease in volume of  securities
                  offered (if the total dollar value of securities offered would
                  not exceed that which was  registered)  and any deviation from
                  the low or high end of the estimated  maximum  offering  range
                  may be  reflected  in the form of  prospectus  filed  with the
                  Commission  pursuant to Rule 424(b) if, in the aggregate,  the
                  changes  in  volume  and  price  represent  no more than a 20%
                  change in the maximum  aggregate  offering  price set forth in
                  the  "Calculation of Registration  Fee" table in the effective
                  registration statement.

                                      II-2



                           (iii)  To  include  any  material   information  with
                  respect to the plan of distribution  not previously  disclosed
                  in the  registration  statement or any material  change to the
                  information in the registration statement.  Provided, however,
                  that  paragraphs  (a)(1)(i) and (a)(1)(ii) do not apply if the
                  registration  statement  is on Form S-3 or Form  S-8,  and the
                  information  required  to  be  included  in  a  post-effective
                  amendment by those paragraphs is contained in periodic reports
                  filed by the  registrant  pursuant  to  Section  13 or Section
                  15(d) of the  Securities  and  Exchange  Act of 1934  that are
                  incorporated by reference in the registration statement.

                  (2) That, for the purpose of determining  any liability  under
         the Securities Act, each of these  post-effective  amendments  shall be
         deemed to be a new  registration  statement  relating to the securities
         being offered,  and the offering of those securities at that time shall
         be deemed to be their initial bona fide offering.

                  (3) To remove from  registration by means of a  post-effective
         amendment any of the securities being registered which remain unsold at
         the termination of the offering.

         (b) The undersigned  Registrant hereby undertakes that, for purposes of
determining  any  liability  under  the  Securities  Act,  each  filing  of  the
Registrant's  annual  report  pursuant to Section  13(a) or Section 15(d) of the
Securities  Exchange  Act of 1934  (and,  where  applicable,  each  filing of an
employee  benefit  plan's  annual  report  pursuant  to  Section  15(d)  of  the
Securities  Exchange  Act of 1934)  that is  incorporated  by  reference  in the
registration  statement  shall  be  deemed  to be a new  registration  statement
relating to the securities  being offered,  and the offering of those securities
at that time shall be deemed to be their initial bona fide offering.

         (c)  Insofar as  directors,  officers  and  controlling  persons of the
Registrant are permitted to seek  indemnification  for liabilities arising under
the Securities Act, under the foregoing provisions, or otherwise, the Registrant
has been advised that in the opinion of the Securities and Exchange  Commission,
this indemnification is against public policy as expressed in the Securities Act
and is,  therefore,  unenforceable.  In the event  that a  director,  officer or
controlling  person asserts a claim for  indemnification  against these types of
liabilities in connection with the securities being  registered,  other than the
payment by the Registrant of expenses incurred or paid by a director, officer or
controlling  person of the Registrant in the  successful  defense of any action,
suit or proceeding,  the Registrant  will,  unless in the opinion of its counsel
the  matter  has been  settled by  controlling  precedent,  submit to a court of
appropriate  jurisdiction the question whether indemnification by it under these
circumstances  is against  public policy as expressed in the  Securities Act and
will be governed by the final adjudication of the issue.

                                      II-3




                                   SIGNATURES

         Pursuant to the  requirements  of the  Securities  Act, the  Registrant
certifies  that it has  reasonable  grounds to believe  that it meets all of the
requirements  for  filing  on Form S-2 and has  duly  caused  this  Registration
Statement  to be  signed  on its  behalf  by  the  undersigned,  thereunto  duly
authorized, in the County of Howard, State of Maryland, on June 12, 2003.

                                    ESSEX CORPORATION


                                    By: /S/ LEONARD E. MOODISPAW
                                    ----------------------------------------
                                        Leonard E. Moodispaw
                                        President and Chief Executive Officer

                                      II-4




         Pursuant to the  requirements of the Securities Act, this  Registration
Statement has been signed by the following  persons in the capacities and on the
dates indicated.

SIGNATURE                                   TITLE                      DATE

/S/ H. JEFFREY LEONARD*             Chairman of the Board         June 12, 2003
----------------------------
H. Jeffrey Leonard


/S/ LEONARD E. MOODISPAW            President, Chief Executive    June 12, 2003
---------------------------         Officer, and Director
Leonard E. Moodispaw                (principal executive officer)


/S/ JOSEPH R. KURRY, JR.            Chief Financial Officer       June 12, 2003
---------------------------         (principal financial
Joseph R. Kurry, Jr.                and accounting officer)


                                    Director                     June    , 2003
---------------------------
John G. Hannon


/S/ ROBERT W. HICKS*                Director                      June 12, 2003
---------------------------
Robert W. Hicks


/S/ RAY M. KEELER*                  Director                      June 12, 2003
---------------------------
Ray M. Keeler

                                    Director                    June     , 2003
---------------------------
Frank E. Manning


/S/ MARIE S. MINTON*                Director                      June 12, 2003
---------------------------
Marie S. Minton


                                    Director                    June     , 2003
---------------------------
Arthur L. Money


/S/ TERRY M. TURPIN*                Director                      June 12, 2003
---------------------------
Terry M. Turpin


* pursuant to a power of attorney dated May 17, 2001 previously  filed with Form
S-3 (No. 333-61200)


                                      II-5