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

                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          DEC-31-2000
<PERIOD-END>                               JUN-30-2000
<CASH>                                          68,967
<SECURITIES>                                   138,958
<RECEIVABLES>                                    4,229
<ALLOWANCES>                                         0
<INVENTORY>                                          0
<CURRENT-ASSETS>                               212,821
<PP&E>                                          11,726
<DEPRECIATION>                                 (5,123)
<TOTAL-ASSETS>                                 286,338
<CURRENT-LIABILITIES>                            6,155
<BONDS>                                              0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                           426
<OTHER-SE>                                     269,757
<TOTAL-LIABILITY-AND-EQUITY>                   286,338
<SALES>                                              0
<TOTAL-REVENUES>                                12,261
<CGS>                                                0
<TOTAL-COSTS>                                        0
<OTHER-EXPENSES>                                11,937
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                                 406
<INCOME-PRETAX>                                  4,182
<INCOME-TAX>                                   (1,700)
<INCOME-CONTINUING>                              2,482
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                     2,482
<EPS-BASIC>                                       0.07
<EPS-DILUTED>                                     0.06