<ARTICLE> 5 <LEGEND> THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THERMO OPTEK CORPORATION'S ANNUAL REPORT ON FORM 10-K FOR THE YEAR ENDED JANUARY 3, 1998 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS. </LEGEND> <MULTIPLIER> 1,000 <PERIOD-TYPE> YEAR <FISCAL-YEAR-END> JAN-03-1998 <PERIOD-END> JAN-03-1998 <CASH> 71,245 <SECURITIES> 0 <RECEIVABLES> 105,051 <ALLOWANCES> 5,709 <INVENTORY> 70,095 <CURRENT-ASSETS> 263,301 <PP&E> 92,711 <DEPRECIATION> 29,970 <TOTAL-ASSETS> 580,536 <CURRENT-LIABILITIES> 195,709 <BONDS> 81,400 <PREFERRED-MANDATORY> 0 <PREFERRED> 0 <COMMON> 516 <OTHER-SE> 287,777 <TOTAL-LIABILITY-AND-EQUITY> 580,536 <SALES> 512,464 <TOTAL-REVENUES> 512,464 <CGS> 276,998 <TOTAL-COSTS> 276,998 <OTHER-EXPENSES> 30,861 <LOSS-PROVISION> 629 <INTEREST-EXPENSE> 10,197 <INCOME-PRETAX> 72,106 <INCOME-TAX> 30,796 <INCOME-CONTINUING> 41,310 <DISCONTINUED> 0 <EXTRAORDINARY> 0 <CHANGES> 0 <NET-INCOME> 41,310 <EPS-PRIMARY> 0.82 <EPS-DILUTED> 0.77