<ARTICLE> 5
<LEGEND>
THE FINANCIAL DATA SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED
FROM TANOX'S 10-Q FOR THE NINE MONTHS ENDED SEPTEMBER 30, 2000 AND IS QUALIFIED
IN ITS ENTIRETY BY REFERENCE TO SUCH MATTERS.
</LEGEND>
<MULTIPLIER> 1,000

                             
<PERIOD-TYPE>                   9-MOS
<FISCAL-YEAR-END>                          DEC-31-2000
<PERIOD-START>                             JAN-01-2000
<PERIOD-END>                               SEP-30-2000
<CASH>                                          39,998
<SECURITIES>                                   235,952
<RECEIVABLES>                                    5,448
<ALLOWANCES>                                         0
<INVENTORY>                                          0
<CURRENT-ASSETS>                               194,138
<PP&E>                                          12,735
<DEPRECIATION>                                 (5,402)
<TOTAL-ASSETS>                                 286,538
<CURRENT-LIABILITIES>                            6,889
<BONDS>                                              0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                           426
<OTHER-SE>                                     269,223
<TOTAL-LIABILITY-AND-EQUITY>                   286,538
<SALES>                                              0
<TOTAL-REVENUES>                                12,464
<CGS>                                                0
<TOTAL-COSTS>                                        0
<OTHER-EXPENSES>                                17,914
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                                 628
<INCOME-PRETAX>                                  2,800
<INCOME-TAX>                                   (2,057)
<INCOME-CONTINUING>                                743
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                       743
<EPS-BASIC>                                       0.02
<EPS-DILUTED>                                     0.02