<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 SEPTEMBER 30, 2000
AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1,000
<S> <C>
<PERIOD-TYPE> 9-MOS
<FISCAL-YEAR-END> DEC-30-2000
<PERIOD-END> SEP-30-2000
<CASH> 10,724
<SECURITIES> 118,457
<RECEIVABLES> 14,512
<ALLOWANCES> 926
<INVENTORY> 16,463
<CURRENT-ASSETS> 163,293
<PP&E> 23,121
<DEPRECIATION> 16,057
<TOTAL-ASSETS> 174,179
<CURRENT-LIABILITIES> 15,673
<BONDS> 53,338
0
0
<COMMON> 4,063
<OTHER-SE> 99,605
<TOTAL-LIABILITY-AND-EQUITY> 174,179
<SALES> 62,235
<TOTAL-REVENUES> 62,235
<CGS> 26,123
<TOTAL-COSTS> 26,123
<OTHER-EXPENSES> 12,646
<LOSS-PROVISION> 0
<INTEREST-EXPENSE> 2,201
<INCOME-PRETAX> 9,285
<INCOME-TAX> 3,573
<INCOME-CONTINUING> 5,712
<DISCONTINUED> 0
<EXTRAORDINARY> 191
<CHANGES> 0
<NET-INCOME> 5,903
<EPS-BASIC> .15
<EPS-DILUTED> .15
</TABLE>