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 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 *
  COHEN AVI
 2. Date of Event Requiring Statement (Month/Day/Year)
11/05/2003		 3. Issuer Name and Ticker or Trading Symbol
KLA TENCOR CORP [KLAC]
(Last)
(First)
(Middle)
C/O KLA-TENCOR CORPORATION, 160 RIO ROBLES		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
VP, Pattern Solutions Group
5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

SAN JOSE, CA 95130		 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 1,145
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
Non-Qualified Stock Option (right to buy) 08/31/1999 08/31/2008 Common Stock 47,313 $ 10.63 D  
Non-Qualified Stock Option (right to buy) 04/30/1998 04/30/2007 Common Stock 7,500 $ 22.25 D  
Non-Qualified Stock Option (right to buy) 11/10/2001 11/10/2010 Common Stock 8,750 $ 26.25 D  
Non-Qualified Stock Option (right to buy) 10/02/2002 10/02/2011 Common Stock 22,500 $ 29.31 D  
Non-Qualified Stock Option (right to buy) 04/04/2002 04/04/2011 Common Stock 8,750 $ 32.75 D  
Non-Qualified Stock Option (right to buy) 10/27/2000 10/27/2009 Common Stock 24,000 $ 33.75 D  
Non-Qualified Stock Option (right to buy) 11/08/2003 01/28/2013 Common Stock 12,500 $ 34.67 D  
Non-Qualified Stock Option (right to buy) 11/08/2003 11/08/2012 Common Stock 6,250 $ 37.05 D  
Non-Qualified Stock Option (right to buy) 08/13/2000 08/13/2010 Common Stock 17,500 $ 44.6875 D  
Non-Qualified Stock Option (right to buy) 11/08/2003 07/30/2013 Common Stock 6,250 $ 51.229 D  
Non-Qualified Stock Option (right to buy) 10/27/2004 10/27/2013 Common Stock 16,000 $ 53.86 D  

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
COHEN AVI
C/O KLA-TENCOR CORPORATION
160 RIO ROBLES
SAN JOSE, CA 95130		       VP, Pattern Solutions Group  

Signatures

By: Stuart J. Nichols For: Avi Cohen 11/14/2003
**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).

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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