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 *
Glasser Lance A
   2. Issuer Name and Ticker or Trading Symbol
KLA TENCOR CORP [KLAC] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Executive Vice President
(Last)
(First)
(Middle)
C/O KLA-TENCOR CORPORATION, 160 RIO ROBLES		 3. Date of Earliest Transaction (Month/Day/Year)
12/03/2004
(Street)

SAN JOSE, CA 95130		 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 12/03/2004   M   2,500 A $ 10.63 5,436 D  
Common Stock 12/03/2004   S   2,500 D $ 49.24 2,936 D  
Common Stock 12/03/2004   M   3,500 A $ 10.63 6,436 D  
Common Stock 12/03/2004   S   3,500 D $ 49.23 2,936 D  
Common Stock-Restricted Stock Units (1)               33,333 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
Non-Qualified Stock Option (right to buy) $ 10.63 12/03/2004   M     2,500 08/31/1999 08/31/2008 Common Stock 2,500 $ 49.24 30,500 D  
Non-Qualified Stock Option (right to buy) $ 10.63 12/03/2004   M     3,500 08/31/1999 08/31/2008 Common Stock 3,500 $ 49.23 27,000 D  
Non-Qualified Stock Option (right to buy) $ 26.25             11/10/2001 11/10/2010 Common Stock 5,000   5,000 D  
Non-Qualified Stock Option (right to buy) $ 29.31             10/02/2002 10/02/2011 Common Stock 22,500   22,500 D  
Non-Qualified Stock Option (right to buy) $ 32.75             04/04/2002 04/04/2011 Common Stock 5,000   5,000 D  
Non-Qualified Stock Option (right to buy) $ 33.75             10/27/2000 10/27/2009 Common Stock 20,000   20,000 D  
Non-Qualified Stock Option (right to buy) $ 34.67             11/08/2003 01/28/2013 Common Stock 9,000   9,000 D  
Non-Qualified Stock Option (right to buy) $ 37.05             11/08/2003 11/08/2012 Common Stock 4,500   4,500 D  
Non-Qualified Stock Option (right to buy) $ 40.66             10/27/2004 08/02/2014 Common Stock 3,750   3,750 D  
Non-Qualified Stock Option (right to buy) $ 41.79             09/21/2005 09/21/2014 Common Stock 75,000   75,000 D  
Non-Qualified Stock Option (right to buy) $ 42.28             11/30/2000 11/30/2009 Common Stock 10,000   10,000 D  
Non-Qualified Stock Option (right to buy) $ 44.6875             08/13/2000 08/13/2010 Common Stock 10,000   10,000 D  
Non-Qualified Stock Option (right to buy) $ 45.16             10/27/2004 04/26/2014 Common Stock 6,250   6,250 D  
Non-Qualified Stock Option (right to buy) $ 51.229             11/08/2003 07/30/2013 Common Stock 4,500   4,500 D  
Non-Qualified Stock Option (right to buy) $ 53.86             10/27/2004 10/27/2013 Common Stock 10,000   10,000 D  
Non-Qualified Stock Option (right to buy) $ 58.1             10/27/2004 01/27/2014 Common Stock 5,000   5,000 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
Glasser Lance A
C/O KLA-TENCOR CORPORATION
160 RIO ROBLES
SAN JOSE, CA 95130		       Executive Vice President  

Signatures

 By: Stuart J. Nichols For: Lance A. Glasser   12/06/2004
**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) Each restricted stock unit represents a contingent right to receive one share of KLAC common stock.

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