Exhibit 31.3

                           THERMO ELECTRON CORPORATION

      CERTIFICATION REQUIRED BY EXCHANGE ACT RULES 13a-14(a) and 15d-14(a),
                             AS ADOPTED PURSUANT TO
                  SECTION 302 OF THE SARBANES-OXLEY ACT OF 2002


I, Marijn E. Dekkers, certify that:

1.       I have reviewed this Amendment No. 1 on Form 10-Q/A of Thermo Electron
         Corporation; and

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.


Date:  August 29, 2005



                                           /s/ Marijn E. Dekkers
                                           -------------------------------------
                                           Marijn E. Dekkers
                                           President and Chief Executive Officer