<ARTICLE>      5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THERMO
INSTRUMENT SYSTEMS INC.'S REPORT ON FORM 10-Q FOR THE PERIOD ENDED OCTOBER 3,
1998 AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER>   1,000
       
                     
<PERIOD-TYPE>                    9-MOS
<FISCAL-YEAR-END>                JAN-02-1999
<PERIOD-END>                     OCT-03-1998
<CASH>                               566,041
<SECURITIES>                           6,021
<RECEIVABLES>                        396,991
<ALLOWANCES>                          25,064
<INVENTORY>                          292,342
<CURRENT-ASSETS>                   1,331,962
<PP&E>                               336,018
<DEPRECIATION>                       119,872
<TOTAL-ASSETS>                     2,551,649
<CURRENT-LIABILITIES>                576,730
<BONDS>                              600,238
<PREFERRED-MANDATORY>                      0
<PREFERRED>                                0
<COMMON>                              12,286
<OTHER-SE>                           905,818
<TOTAL-LIABILITY-AND-EQUITY>       2,551,649
<SALES>                            1,210,345
<TOTAL-REVENUES>                   1,210,345
<CGS>                                649,118
<TOTAL-COSTS>                        649,118
<OTHER-EXPENSES>                     107,643
<LOSS-PROVISION>                       1,508
<INTEREST-EXPENSE>                    34,735
<INCOME-PRETAX>                      139,806
<INCOME-TAX>                          50,948
<INCOME-CONTINUING>                   78,333
<DISCONTINUED>                             0
<EXTRAORDINARY>                          195
<CHANGES>                                  0
<NET-INCOME>                          78,528
<EPS-PRIMARY>                           0.65
<EPS-DILUTED>                           0.60