<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THERMO OPTEK
CORPORATION'S QUARTERLY REPORT ON FORM 10-Q FOR THE QUARTER ENDED JUNE 28, 1997
AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
       
                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          JAN-03-1998
<PERIOD-END>                               JUN-28-1997
<CASH>                                          81,771
<SECURITIES>                                         0
<RECEIVABLES>                                  100,855
<ALLOWANCES>                                     5,793
<INVENTORY>                                     82,683
<CURRENT-ASSETS>                               281,663
<PP&E>                                          90,161
<DEPRECIATION>                                  27,267
<TOTAL-ASSETS>                                 617,309
<CURRENT-LIABILITIES>                          241,166
<BONDS>                                          1,792
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                           485
<OTHER-SE>                                     260,578
<TOTAL-LIABILITY-AND-EQUITY>                   617,309
<SALES>                                        223,192
<TOTAL-REVENUES>                               223,192
<CGS>                                          119,943
<TOTAL-COSTS>                                  119,943
<OTHER-EXPENSES>                                12,975
<LOSS-PROVISION>                                   114
<INTEREST-EXPENSE>                               3,884
<INCOME-PRETAX>                                 32,767
<INCOME-TAX>                                    14,090
<INCOME-CONTINUING>                             18,677
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    18,677
<EPS-PRIMARY>                                      .39
<EPS-DILUTED>                                      .37