<TABLE> <S> <C>
<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM
THERMO CARDIOSYSTEMS INC.'S
QUARTERLY REPORT ON FORM 10-Q FOR THE PERIOD ENDED JULY 1, 2000
AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
<S> <C>
<PERIOD-TYPE> 6-MOS
<FISCAL-YEAR-END> DEC-30-2000
<PERIOD-END> JUL-01-2000
<CASH> 435
<SECURITIES> 102,146
<RECEIVABLES> 16,183
<ALLOWANCES> 949
<INVENTORY> 15,215
<CURRENT-ASSETS> 160,313
<PP&E> 22,587
<DEPRECIATION> 15,307
<TOTAL-ASSETS> 171,453
<CURRENT-LIABILITIES> 14,738
<BONDS> 53,338
0
0
<COMMON> 4,063
<OTHER-SE> 97,814
<TOTAL-LIABILITY-AND-EQUITY> 171,453
<SALES> 42,844
<TOTAL-REVENUES> 42,844
<CGS> 17,824
<TOTAL-COSTS> 17,824
<OTHER-EXPENSES> 7,650
<LOSS-PROVISION> 0
<INTEREST-EXPENSE> 1,494
<INCOME-PRETAX> 6,859
<INCOME-TAX> 2,641
<INCOME-CONTINUING> 4,218
<DISCONTINUED> 0
<EXTRAORDINARY> 191
<CHANGES> 0
<NET-INCOME> 4,409
<EPS-BASIC> .11
<EPS-DILUTED> .11
</TABLE>