<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE BALANCE
SHEETS AND CONSOLIDATED STATEMENTS OF OPERATIONS OF THORATEC LABORATORIES
CORPORATION AND IS QUALIFIED IN ITS ENTIRETY BY REFERENCE TO SUCH ANNUAL REPORT
ON FORM 10K PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES AND EXCHANGE ACT
OF 1934 FOR THE FISCAL YEAR ENDED JANUARY 2, 1999.
</LEGEND>
       
                             
<PERIOD-TYPE>                   YEAR
<FISCAL-YEAR-END>                          JAN-02-1999
<PERIOD-START>                             JAN-04-1998
<PERIOD-END>                               JAN-02-1999
<CASH>                                       2,712,686
<SECURITIES>                                 2,032,107
<RECEIVABLES>                                4,141,854
<ALLOWANCES>                                    47,591
<INVENTORY>                                  5,290,745
<CURRENT-ASSETS>                            14,582,129
<PP&E>                                      12,460,755
<DEPRECIATION>                             (2,835,365)
<TOTAL-ASSETS>                              25,208,417
<CURRENT-LIABILITIES>                        3,331,060
<BONDS>                                              0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                    72,810,450
<OTHER-SE>                                (53,402,106)
<TOTAL-LIABILITY-AND-EQUITY>                25,208,417
<SALES>                                     16,319,531
<TOTAL-REVENUES>                            16,980,916
<CGS>                                        6,503,986
<TOTAL-COSTS>                                6,503,986
<OTHER-EXPENSES>                            12,797,482
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                                   0
<INCOME-PRETAX>                            (2,320,552)
<INCOME-TAX>                                         0
<INCOME-CONTINUING>                        (2,320,552)
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                               (2,320,552)
<EPS-PRIMARY>                                    (.11)
<EPS-DILUTED>                                    (.11)