Exhibit 32.1

      CERTIFICATION OF CHIEF EXECUTIVE OFFICER AND CHIEF FINANCIAL OFFICER
                                   PURSUANT TO
                             18 U.S.C. SECTION 1350,
                             AS ADOPTED PURSUANT TO
                  SECTION 906 OF THE SARBANES-OXLEY ACT OF 2002

Each of the  undersigned  hereby  certifies,  for purposes of Section 906 of the
Sarbanes-Oxley  Act of  2002,  in his  capacity  as an  officer  of  Nanometrics
Incorporated (the "Company") that based on his knowledge:

         1.       The Annual  Report on Form 10-K of the  Company for the annual
                  period ended  January 3, 2004 (the  "Report")  fully  complies
                  with the  requirements  of Section 13(a) or Section 15(d),  as
                  applicable,  of  the  Securities  Exchange  Act  of  1934,  as
                  amended; and

         2.       The information  contained in the Report fairly  presents,  in
                  all material respects,  the financial condition and results of
                  operations of the Company.


Date:  March 31, 2004       By:      /s/ John D. Heaton
                                     -------------------------
                            Name:    John D. Heaton
                            Title:   Chief Executive Officer




Date:  March 31, 2004       By:      /s/ Paul B. Nolan
                                     -------------------------
                            Name:    Paul B. Nolan
                            Title:   Chief Financial Officer