SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549
SCHEDULE 13G
Under the Securities Exchange Act of 1934
Amendment # 5
Name of
Issuer: KLA TENCOR CORP
_____________________________________________________
Title of Class
of Securities: Common Stock
CUSIP Number: 482480100
1) NAME OF I.R.S. IDENTIFICATION NO. OF REPORTING PERSON
The Prudential Insurance Company of America 22-1211670
2.) MEMBER OF A GROUP: (a) N/A
(b) N/A
3) SEC USE ONLY:
4) PLACE OF ORGANIZATION: A mutual insurance company organized
under the laws of the State of New Jersey
NUMBER OF SHARES BENEFICIALLY OWNED BY REPORTING PERSON WITH:
5) Sole Voting Power: 344,400 See Exhibit
A
6) Shared Voting Power: 3,951,113 See Exhibit A
7) Sole Dispositive Power: 344,400 See Exhibit A
8) Shared Dispositive Power: 4,257,236 See Exhibit
A
9) AGGREGATE AMOUNT BENEFICIALLY OWNED:
4,601,636 See Exhibit A
10) AGGREGATE AMOUNT IN ROW (9) EXCLUDES SHARES: Not Applicable
11) PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9):
5.12 See Exhibit A
12) TYPE OF REPORTING PERSON: IC, IA
ITEM 1(a). NAME OF ISSUER:
KLA TENCOR CORP
ITEM 1(b). ADDRESS OF ISSUER'S EXECUTIVE OFFICES:
KLA TENCOR CORP
160 Rio Robles
San Jose, CA 95134
ITEM 2(a). NAME OF PERSON FILING:
The Prudential Insurance Company of America
ITEM 2(b). ADDRESS OF PRINCIPAL BUSINESS OFFICE:
751 Broad Street
Newark, New Jersey 07102-3777
ITEM 2(c). CITIZENSHIP:
A mutual insurance company organized under the
laws of
the State of New Jersey
ITEM 2(d). TITLE OF CLASS OF SECURITIES:
Common Stock
ITEM 2(e). CUSIP NUMBER:
482480100
ITEM 3. The Person filing this statement is an Insurance
Company
as defined in Section 3(a) (19) of the Securities
Exchange
Act of 1934, and an Investment Adviser registered
under
Section 203 of the Investment Advisers Act of
1940.
ITEM 4. OWNERSHIP:
(a) Number of Shares
Beneficially Owned: 4,601,636 See
Exhibit A
(b) Percent of Class: 5.12
Number
(c) Powers Of Shares
-------------------------------------
- -------------------------------------
Sole power to vote or 344,400
See Exhibit A
to direct the vote
Shared power to vote or 3,951,113
See Exhibit A
to direct the vote
Sole power to dispose or 344,400
See Exhibit A
to direct disposition
Shared power to dispose 4,257,236
See Exhibit A
or to direct disposition
ITEM 5. OWNERSHIP OF 5% OR LESS OF A CLASS:
Not Applicable
ITEM 6. OWNERSHIP OF MORE THAN 5% ON BEHALF OF
ANOTHER PERSON:
See Exhibit A
ITEM 7. IDENTIFICATION AND CLASSIFICATION OF THE
SUBSIDIARY WHICH ACQUIRED THE SECURITY BEING
REPORTED ON BY THE ULTIMATE PARENT COMPANY:
Not Applicable
ITEM 8. IDENTIFICATION AND CLASSIFICATION OF
MEMBERS OF THE GROUP:
Not Applicable
ITEM 9. NOTICE OF DISSOLUTION OF GROUP:
Not Applicable
ITEM 10. CERTIFICATION:
By signing below, the Prudential Insurance Company of America
certifies that, to the best of its knowledge and belief, the
securities referred to above were acquired in the ordinary course
of business and were not acquired for the purpose of and do not
have the effect of changing or influencing the control of the
issuer of such securities and were not acquired in connection
with or as a participant in any transaction having such purpose
or effect.
The filing of this statement should not be construed as an
admission that
Prudential is, for purposes of Sections 13 or 16 of the Securities
Exchange Act of 1934, the beneficial owner of such shares.
SIGNATURE
After reasonable inquiry and to the best of its knowledge and
belief, The Prudential Insurance Company of America certifies that
the information set forth in this statement is true, complete and
correct.
THE PRUDENTIAL INSURANCE COMPANY OF AMERICA
By: Ellen McGlynn Koke
Vice President
Date: 01/31/2000
As of: 12/31/1999
Exhibit A
--------------
ITEM 6. OWNERSHIP:
The Prudential Insurance Company of America ('Prudential') presently holds
21,500 shares of Issuer's common stock for the benefit of its general
account.
In addition, Prudential may have direct or indirect voting and/or
investment discretion over
4,580,136 shares which are held for its own benefit or for the benefit of
its clients by its separate accounts, externally managed accounts,
registered investment companies, subsidiaries and/or other affiliates.
Prudential is reporting the combined holdings of these entities for the
purpose of administrative convenience.
These shares were acquired in the ordinary course of business, and not
with the purpose or effect of changing or influencing control of the
Issuer. The filing of this statement should not be construed as an
admission that Prudential is, for the purposes of Sections 13 or 16 of the
Securities Exchange Act of 1934, the beneficial owner of these shares.
