<ARTICLE> 5
<LEGEND>
THIS SCHEDULE CONTAINS FINANCIAL INFORMATION EXTRACTED FROM THE FINANCIAL
STATEMENTS FOR REPLIGEN CORPORATION AND IS QUALIFIED IN ITS ENTIRETY BY
REFERENCE TO SUCH FINANCIAL STATEMENTS.

<MULTIPLIER> 1,000

                             
<PERIOD-TYPE>                   6-MOS
<FISCAL-YEAR-END>                          MAR-31-2000
<PERIOD-END>                               SEP-30-2000
<CASH>                                          27,372
<SECURITIES>                                     5,869
<RECEIVABLES>                                      575
<ALLOWANCES>                                      (25)
<INVENTORY>                                        550
<CURRENT-ASSETS>                                34,215
<PP&E>                                           1,825
<DEPRECIATION>                                 (1,323)
<TOTAL-ASSETS>                                  34,773
<CURRENT-LIABILITIES>                              968
<BONDS>                                              0
<PREFERRED-MANDATORY>                                0
<PREFERRED>                                          0
<COMMON>                                           266
<OTHER-SE>                                      33,540
<TOTAL-LIABILITY-AND-EQUITY>                    34,773
<SALES>                                            880
<TOTAL-REVENUES>                                 2,190
<CGS>                                              559
<TOTAL-COSTS>                                    4,373
<OTHER-EXPENSES>                                     0
<LOSS-PROVISION>                                     0
<INTEREST-EXPENSE>                                   0
<INCOME-PRETAX>                                      0
<INCOME-TAX>                                         0
<INCOME-CONTINUING>                                  0
<DISCONTINUED>                                       0
<EXTRAORDINARY>                                      0
<CHANGES>                                            0
<NET-INCOME>                                   (2,183)
<EPS-BASIC>                                     (0.08)
<EPS-DILUTED>                                   (0.08)