<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 1,2000
AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER>        1,000

                              
<PERIOD-TYPE>                                 3-MOS
<FISCAL-YEAR-END>                             DEC-30-2000
<PERIOD-END>                                  APR-01-2000
<CASH>                                                188,588
<SECURITIES>                                                0
<RECEIVABLES>                                         487,378
<ALLOWANCES>                                           29,315
<INVENTORY>                                           345,924
<CURRENT-ASSETS>                                    1,379,874
<PP&E>                                                443,154
<DEPRECIATION>                                        160,742
<TOTAL-ASSETS>                                      2,851,282
<CURRENT-LIABILITIES>                                 969,722
<BONDS>                                               451,561
<PREFERRED-MANDATORY>                                       0
<PREFERRED>                                                 0
<COMMON>                                               13,400
<OTHER-SE>                                          1,116,498
<TOTAL-LIABILITY-AND-EQUITY>                        2,851,282
<SALES>                                               521,086
<TOTAL-REVENUES>                                      521,086
<CGS>                                                 276,202
<TOTAL-COSTS>                                         276,202
<OTHER-EXPENSES>                                       32,365
<LOSS-PROVISION>                                        1,304
<INTEREST-EXPENSE>                                     12,583
<INCOME-PRETAX>                                        43,270
<INCOME-TAX>                                           19,482
<INCOME-CONTINUING>                                    19,332
<DISCONTINUED>                                              0
<EXTRAORDINARY>                                             0
<CHANGES>                                                   0
<NET-INCOME>                                           19,332
<EPS-BASIC>                                            0.16
<EPS-DILUTED>                                            0.15