<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THERMO
INSTRUMENT SYSTEMS INC.'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>                                         678,595
<SECURITIES>                                     8,496
<RECEIVABLES>                                  369,448
<ALLOWANCES>                                    22,675
<INVENTORY>                                    274,597
<CURRENT-ASSETS>                             1,397,480
<PP&E>                                         318,302
<DEPRECIATION>                                 104,923
<TOTAL-ASSETS>                               2,550,295
<CURRENT-LIABILITIES>                          569,596
<BONDS>                                        612,590
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                        12,277
<OTHER-SE>                                     889,780
<TOTAL-LIABILITY-AND-EQUITY>                 2,550,295
<SALES>                                        407,943
<TOTAL-REVENUES>                               407,943
<CGS>                                          214,209
<TOTAL-COSTS>                                  214,209
<OTHER-EXPENSES>                                28,519
<LOSS-PROVISION>                                   185
<INTEREST-EXPENSE>                              11,493
<INCOME-PRETAX>                                 64,114
<INCOME-TAX>                                    21,959
<INCOME-CONTINUING>                             37,855
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                    37,855
<EPS-PRIMARY>                                      .31
<EPS-DILUTED>                                      .28