Ownership Submission
FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF 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 *
  Hensel Julie A
 2. Date of Event Requiring Statement (Month/Day/Year)
10/04/2005		 3. Issuer Name and Ticker or Trading Symbol
CABOT MICROELECTRONICS CORP [CCMP]
(Last)
(First)
(Middle)
C/O CABOT MICROELECTRONICS CORPORATION, 870 COMMONS DRIVE		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Vice President Global Quality
 5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

AURORA, IL 60504		 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 Beneficially Owned
1.Title of Security
(Instr. 4)		 2. Amount of Securities Beneficially Owned
(Instr. 4)		 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)		 4. Nature of Indirect Beneficial Ownership
(Instr. 5)
Common Stock 242.104
D
 

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)		 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)		 6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Stock Options (Right to buy) 12/10/2004(1) 12/10/2014 Common Stock 15,000 $ 37.78 D  
Stock Options (Right to buy) 03/29/2005(2) 03/29/2014 Common Stock 2,000 $ 43.73 D  

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
Hensel Julie A
C/O CABOT MICROELECTRONICS CORPORATION
870 COMMONS DRIVE
AURORA, IL 60504		       Vice President Global Quality  

Signatures

H.Carol Bernstein 10/07/2005
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(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).
(2) Vesting Schedule: 25% 3/29/05 75% 9/1/05
(1) Vesting Schedule: 25% 12/10/05 25% 12/10/06 25% 12/10/07 25% 12/10/08

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

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