Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
OMB APPROVAL
OMB Number: 3235-0287
Expires: January 31, 2005
Estimated average burden hours per response... 0.5

(Print or Type Responses)
1. Name and Address of Reporting Person *
SHILLMAN ROBERT J
   2. Issuer Name and Ticker or Trading Symbol
COGNEX CORP [CGNX] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director __X__ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
President & CEO
(Last)
(First)
(Middle)
COGNEX CORPORATION, ONE VISION DRIVE		 3. Date of Earliest Transaction (Month/Day/Year)
12/01/2005
(Street)

NATICK, MA 01760		 4. If Amendment, Date Original Filed(Month/Day/Year)
 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)		 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)		 4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)		 5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
Common Stock (1) 12/01/2005   S   65,000 D $ 31.2148 3,535,506 D  
Common Stock               65,000 I by Trust

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number. SEC 1474 (9-02)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)		 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)		 5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)		 6. Date Exercisable and Expiration Date
(Month/Day/Year)		 7. Title and Amount of Underlying Securities
(Instr. 3 and 4)		 8. Price of Derivative Security
(Instr. 5)		 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Non-Qualified Stock Option (right to buy) $ 18.125             04/27/2005 12/21/2015 Common Stock 60,000   60,000 D  
Non-Qualified Stock Option (right to buy) $ 21.195             01/01/2004 04/02/2013 Common Stock 41,250   41,250 D  
Non-Qualified Stock Option (right to buy) $ 21.74             01/01/2003 02/11/2012 Common Stock 24,000   24,000 D  
Non-Qualified Stock Option (right to buy) $ 22.685             04/01/2002 03/13/2011 Common Stock 2,250   2,250 D  
Non-Qualified Stock Option (right to buy) $ 24.66             01/01/2002 06/25/2011 Common Stock 39,200   39,200 D  
Non-Qualified Stock Option (right to buy) $ 25.02             01/01/2006 01/10/2015 Common Stock 50,000   50,000 D  
Non-Qualified Stock Option (right to buy) $ 28.954             04/27/2002 04/27/2009 Common Stock 62,400   62,400 D  
Non-Qualified Stock Option (right to buy) $ 29.35             07/22/2005 07/22/2014 Common Stock 5,000   5,000 D  
Non-Qualified Stock Option (right to buy) $ 30.813             04/27/2004 12/14/2014 Common Stock 35,000   35,000 D  
Non-Qualified Stock Option (right to buy) $ 31.94             01/01/2005 02/25/2014 Common Stock 115,000   115,000 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
SHILLMAN ROBERT J
COGNEX CORPORATION
ONE VISION DRIVE
NATICK, MA 01760		   X   X   President & CEO  

Signatures

 Robert J Shillman   12/01/2005
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) 700 Shares held by Reporting Person's spouse. The Reporting Person disclaims beneficial ownership of these shares. 7,000 Shares held by Reporting Person's children. The Reporting Person disclaims beneficial ownership of these shares.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.