<ARTICLE> 5 <LEGEND> THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THERMO OPTEK CORPORATION'S QUARTERLY REPORT ON FORM 10-Q FOR THE PERIOD ENDED APRIL 4, 1998 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS. </LEGEND> <MULTIPLIER> 1,000 <PERIOD-TYPE> 3-MOS <FISCAL-YEAR-END> JAN-02-1999 <PERIOD-END> APR-04-1998 <CASH> 95,712 <SECURITIES> 0 <RECEIVABLES> 100,104 <ALLOWANCES> 5,579 <INVENTORY> 69,197 <CURRENT-ASSETS> 277,471 <PP&E> 93,055 <DEPRECIATION> 32,078 <TOTAL-ASSETS> 590,580 <CURRENT-LIABILITIES> 197,323 <BONDS> 81,286 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 517 <OTHER-SE> 296,615 <TOTAL-LIABILITY-AND-EQUITY> 590,580 <SALES> 113,799 <TOTAL-REVENUES> 113,799 <CGS> 60,959 <TOTAL-COSTS> 60,959 <OTHER-EXPENSES> 6,384 <LOSS-PROVISION> 85 <INTEREST-EXPENSE> 1,902 <INCOME-PRETAX> 16,769 <INCOME-TAX> 6,959 <INCOME-CONTINUING> 9,810 <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 9,810 <EPS-PRIMARY> 0.19 <EPS-DILUTED> 0.18