Exhibit 31.2

I, Paul B. Nolan, certify that:

1.       I have  reviewed  this  quarterly  report on Form  10-Q of  Nanometrics
         Incorporated;

2.       Based on my  knowledge,  this  quarterly  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 quarterly report;

3.       Based on my knowledge,  the financial  statements,  and other financial
         information  included in this quarterly  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 quarterly report;

4.       The registrant's  other  certifying  officers 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:

              (b)   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
                    quarterly 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 quarterly report based on such evaluation; and

              (c)   disclosed  in  this  quarterly  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 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
         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.



Date:  August 23, 2004                         By: /s/ Paul B. Nolan
                                                  ------------------------------
                                               Name:    Paul B. Nolan
                                               Title:   Chief Financial Officer



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