<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM (A) THE
BALANCE SHEETS, STATEMENTS OF OPERATIONS AND STATEMENTS OF CASH FLOWS OF
THORATEC LABORATORIES CORPORATION AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE
TO SUCH (B) QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES
AND EXCHANGE ACT OF 1934 FOR THE QUARTERLY PERIOD ENDED APRIL 1, 2000.
</LEGEND>
<MULTIPLIER> 1
<CURRENCY> US DOLLARS

                             
<PERIOD-TYPE>                   3-MOS
<FISCAL-YEAR-END>                          DEC-30-2000
<PERIOD-START>                             JAN-02-2000
<PERIOD-END>                               APR-01-2000
<EXCHANGE-RATE>                                      1
<CASH>                                       2,536,395
<SECURITIES>                                         0
<RECEIVABLES>                                5,708,961
<ALLOWANCES>                                         0
<INVENTORY>                                  7,298,507
<CURRENT-ASSETS>                            15,876,117
<PP&E>                                      12,287,096
<DEPRECIATION>                             (2,994,269)
<TOTAL-ASSETS>                              26,619,721
<CURRENT-LIABILITIES>                        4,144,794
<BONDS>                                              0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                    73,691,498
<OTHER-SE>                                (51,999,674)
<TOTAL-LIABILITY-AND-EQUITY>                26,619,721
<SALES>                                      7,605,836
<TOTAL-REVENUES>                             8,012,161
<CGS>                                        2,931,969
<TOTAL-COSTS>                                2,931,969
<OTHER-EXPENSES>                             4,368,717
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                                   0
<INCOME-PRETAX>                                711,475
<INCOME-TAX>                                    62,901
<INCOME-CONTINUING>                            648,574
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                   648,574
<EPS-BASIC>                                      .03
<EPS-DILUTED>                                      .03