<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THERMO OPTEK
CORP.'S QUARTERLY REPORT ON FORM 10-Q FOR THE QUARTER ENDED SEPTEMBER 28, 1996
AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
       
                             
<PERIOD-TYPE>                   9-MOS
<FISCAL-YEAR-END>                          DEC-28-1996
<PERIOD-END>                               SEP-28-1996
<CASH>                                         114,166
<SECURITIES>                                         0
<RECEIVABLES>                                   78,497
<ALLOWANCES>                                     5,781
<INVENTORY>                                     60,794
<CURRENT-ASSETS>                               276,907
<PP&E>                                          73,365
<DEPRECIATION>                                  20,347
<TOTAL-ASSETS>                                 537,456
<CURRENT-LIABILITIES>                          181,135
<BONDS>                                         96,819
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                           485
<OTHER-SE>                                     240,883
<TOTAL-LIABILITY-AND-EQUITY>                   241,368
<SALES>                                        253,682
<TOTAL-REVENUES>                               253,682
<CGS>                                          134,987
<TOTAL-COSTS>                                  134,987
<OTHER-EXPENSES>                                16,644
<LOSS-PROVISION>                                 1,483
<INTEREST-EXPENSE>                               4,974
<INCOME-PRETAX>                                 28,157
<INCOME-TAX>                                    12,011
<INCOME-CONTINUING>                             16,146
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    16,146
<EPS-PRIMARY>                                      .35
<EPS-DILUTED>                                        0