<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS SUMMARY FINANCIAL INFORMATION EXTRACTED FROM THE GELTEX
PHARMACEUTICALS, INC. FORM 10-Q AND THE NOTES THERETO FOR THE QUARTERLY PERIOD
ENDED MARCH 31, 1999 AND IS QUALIFITED IN ITS ENTIRETY BY REFERENCE TO SUCH
FINANCIAL STATEMENTS.
</LEGEND>
<MULTIPLIER> 1
<CURRENCY> U.S. DOLLARS
       
                             
<PERIOD-TYPE>                   3-MOS
<FISCAL-YEAR-END>                          DEC-31-1999
<PERIOD-START>                             JAN-01-1999
<PERIOD-END>                               MAR-31-1999
<EXCHANGE-RATE>                                      1
<CASH>                                      23,079,762
<SECURITIES>                                70,236,794
<RECEIVABLES>                                        0
<ALLOWANCES>                                         0
<INVENTORY>                                    776,954
<CURRENT-ASSETS>                           107,908,044
<PP&E>                                      11,782,000
<DEPRECIATION>                               3,834,484
<TOTAL-ASSETS>                             123,988,363
<CURRENT-LIABILITIES>                        6,451,757
<BONDS>                                              0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                       168,447
<OTHER-SE>                                 112,161,979
<TOTAL-LIABILITY-AND-EQUITY>               123,988,363
<SALES>                                              0
<TOTAL-REVENUES>                             3,634,583
<CGS>                                                0
<TOTAL-COSTS>                               12,519,743
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                             134,404
<INCOME-PRETAX>                            (7,737,060)
<INCOME-TAX>                                         0
<INCOME-CONTINUING>                                  0
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                               (7,737,060)
<EPS-PRIMARY>                                    (.46)
<EPS-DILUTED>                                    (.46)