Exhibit 31.2

                                Certification of Chief Financial Officer
                      Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002

I, John H. Kispert certify that:

     1.   I have  reviewed  this  annual  report on Form  10-K/A  of  KLA-Tencor
          Corporation;

     2.   Based on my  knowledge,  this  report  does  not  contain  any  untrue
          statement  of a  material  fact  or  omit to  state  a  material  fact
          necessary to make the statements  made, in light of the  circumstances
          under which such  statements were made, not misleading with respect to
          the period covered by this report;

     3.   Based on my knowledge,  the financial statements,  and other financial
          information  included in this report,  fairly  present in all material
          respects the financial condition, results of operations and cash flows
          of the  registrant  as of,  and for,  the  periods  presented  in this
          report;

     4.   The registrant's  other  certifying  officer and I are responsible for
          establishing  and maintaining  disclosure  controls and procedures (as
          defined  in  Exchange  Act  Rules  13a-15(e)  and  15d-15(e))  for the
          registrant and have:

     a)   designed  such  disclosure  controls  and  procedures,  or caused such
          disclosure   controls  and   procedures  to  be  designed   under  our
          supervision,  to ensure  that  material  information  relating  to the
          registrant,  including its consolidated subsidiaries, is made known to
          us by others within those entities,  particularly during the period in
          which this report is being prepared;

     b)   evaluated the  effectiveness of the registrant's  disclosure  controls
          and procedures and presented in this report our conclusions  about the
          effectiveness of the disclosure controls and procedures, as of the end
          of the period covered by this report based on such evaluation; and

     c)   disclosed  in this  report  any  change in the  registrant's  internal
          control over financial reporting that occurred during the registrant's
          most recent fiscal quarter (the registrant's  fourth fiscal quarter in
          the case of an annual  report)  that has  materially  affected,  or is
          reasonably  likely to materially  affect,  the  registrant's  internal
          control over the financial reporting; and

     5.   The registrant's other certifying officer and I have disclosed,  based
          on our most recent  evaluation  of  internal  control  over  financial
          reporting, to the registrant's auditors and the audit committee of the
          registrant's  board of directors (or persons performing the equivalent
          functions):

     a)   all significant  deficiencies and material weaknesses in the design or
          operation  of internal  control  over  financial  reporting  which are
          reasonably  likely to  adversely  affect the  registrant's  ability to
          record, process, summarize and report financial information; and

     b)   any fraud, whether or not material,  that involves management or other
          employees who have a  significant  role in the  registrant's  internal
          control over financial reporting.

         September 29, 2003                       /s/ JOHN H. KISPERT
         (Date)                                       John H. Kispert
                                                Executive Vice President
                                                and Chief Financial Officer
                                              (Principal Accounting Officer)