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
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(Print or Type Responses)
1. Name and Address of Reporting Person *
WILKINSON STEVEN V
   2. Issuer Name and Ticker or Trading Symbol
CABOT MICROELECTRONICS CORP [CCMP] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
__X__ Director _____ 10% Owner
_____ Officer (give title below) _____ Other (specify below)
(Last)
(First)
(Middle)
C/O CABOT MICROELECTRONICS CORPORATION, 870 COMMONS DRIVE		 3. Date of Earliest Transaction (Month/Day/Year)
01/17/2005
(Street)

AURORA, IL 60504		 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               9,360 D  

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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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
Stock Options (Right to buy) $ 38.34             03/11/2004 03/11/2013 Common Stock 7,500   7,500 D  
Stock Options (Right to buy) $ 42.44             03/09/2005 03/09/2014 Common Stock 10,000   10,000 D  
Stock Options (Right to buy) $ 46.875             03/13/2002 03/13/2008 Common Stock 7,500   7,500 D  
Stock Options (Right to buy) $ 65.73             03/12/2003 03/12/2012 Common Stock 7,500   7,500 D  
Phantom Stock $ 27.45             07/21/2004 07/21/2004 Common Stock 36.4299   36.4299 D  
Phantom Stock $ 28.05             06/14/2004 06/14/2004 Common Stock 374.3316   374.3316 D  
Phantom Stock $ 34.3             09/28/2004 09/28/2004 Common Stock 87.4636   87.4636 D  
Phantom Stock $ 34.39             08/23/2004 08/23/2004 Common Stock 29.0782   29.0782 D  
Phantom Stock $ 36.5             10/06/2004 10/06/2004 Common Stock 27.3973   27.3973 D  
Phantom Stock $ 36.51 01/17/2005   J(1)   27.3898   01/17/2005 01/17/2005(2) Common Stock 27.3898 $ 0 27.3898 D  
Phantom Stock $ 39.18             12/07/2004 12/07/2004 Common Stock 76.5697   76.5697 D  
Phantom Stock $ 42.44             03/09/2004 03/09/2004 Common Stock 754.0057   754.0057 D  
Phantom Stock $ 50.1             12/08/2003 12/08/2003 Common Stock 59.8802   59.8802 D  
Phantom Stock $ 50.95             06/17/2003 06/17/2003 Common Stock 1,824.0443   1,824.0443 D  
Phantom Stock $ 52.5             11/05/2003 11/05/2003 Common Stock 19.0476   19.0476 D  
Phantom Stock $ 55.37             11/03/2003 11/03/2003 Common Stock 126.4223   126.4223 D  
Phantom Stock $ 59.05             09/23/2003 09/23/2003 Common Stock 50.8044   50.8044 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
WILKINSON STEVEN V
C/O CABOT MICROELECTRONICS CORPORATION
870 COMMONS DRIVE
AURORA, IL 60504		   X      

Signatures

 H. Carol Bernstein   01/19/2005
**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) Rights to acquire shares pursuant to Directors' Deferred Compensation Plan adopted March 12, 2001 as amended June 17, 2003.
(2) Rights to aquire shares pursuant to Directors' Deferred Compensation Plan are already earned.

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