<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THERMEDICS
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>                                         151,403
<SECURITIES>                                    79,133
<RECEIVABLES>                                   61,696
<ALLOWANCES>                                     4,094
<INVENTORY>                                     60,953
<CURRENT-ASSETS>                               361,840
<PP&E>                                          56,913
<DEPRECIATION>                                  35,552
<TOTAL-ASSETS>                                 531,818
<CURRENT-LIABILITIES>                           69,491
<BONDS>                                        131,252
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                         4,174
<OTHER-SE>                                     237,424
<TOTAL-LIABILITY-AND-EQUITY>                   531,818
<SALES>                                         75,661
<TOTAL-REVENUES>                                75,661
<CGS>                                           38,661
<TOTAL-COSTS>                                   38,661
<OTHER-EXPENSES>                                 6,629
<LOSS-PROVISION>                                   111
<INTEREST-EXPENSE>                               1,206
<INCOME-PRETAX>                                 11,787
<INCOME-TAX>                                     4,769
<INCOME-CONTINUING>                              5,368
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                  1,205
<CHANGES>                                            0
<NET-INCOME>                                     6,573
<EPS-PRIMARY>                                      .13
<EPS-DILUTED>                                      .16