Filed Pursuant to Rule 424(b)(3)
                                            Registration Statement No. 333-30383
    

PROSPECTUS
                                 642,847 Shares

                              Repligen Corporation
                                  Common Stock
                       -----------------------------------

     This Prospectus relates to the resale of up to 642,847 shares (the
"Shares") of the common stock, par value $.01 per share (the "Common Stock"), of
Repligen Corporation ("Repligen" or the "Company") by certain holders of Common
Stock of the Company (the "Selling Stockholders"). The Selling Stockholders may
sell the Shares from time to time in transactions on the Nasdaq National Market
("Nasdaq"), in negotiated transactions, through the writing of options on the
Shares, or a combination of such methods of sale, at fixed prices that may be
changed, at market prices prevailing at the time of sale, at prices related to
such prevailing market prices, or at negotiated prices. The Selling Stockholders
may effect these transactions by selling the Shares to or through
broker-dealers, who may receive compensation in the form of discounts or
commissions from the Selling Stockholders or from the purchasers of the Shares
for whom the broker-dealers may act as an agent or to whom they may sell as
principal, or both. See "Selling Stockholders" and "Plan of Distribution."
Certain of the Selling Stockholders acquired an aggregate of 399,243 Shares on
December 30, 1996 and March 31, 1997 in connection with the exchange by the
Company of all of the outstanding capital stock and warrants of ProsCure, Inc.,
a partly-owned subsidiary of the Company ("ProsCure"), for Common Stock of the
Company pursuant to the terms and conditions of the exchange offer (the
"Exchange Offer"), by and between the Company, and each holder of capital stock,
including warrants, preferred stock and common stock, of ProsCure (the
"Exchange"). Others of the Selling Stockholders received an aggregate of 243,604
Shares of Repligen Common Stock pursuant to a Plan of Reorganization and
Agreement of Merger dated March 14, 1996 by and between Repligen, Repligen
Acquisition Corp., a subsidiary of the Company, and Glycan Pharmaceuticals, Inc.
(the "Merger Agreement"). See "Selling Stockholders".

     The Company will not receive any of the proceeds from the sale of the
Shares. See "Use of Proceeds" and "Plan of Distribution." The Company has agreed
to bear all of the expenses in connection with the registration and sale of the
Shares (other than selling commissions), except as otherwise set forth in the
Exchange Offer or the Merger Agreement. See "Plan of Distribution." The Company
has agreed to indemnify the Selling Stockholders against certain liabilities,
including liabilities under the Securities Act.

     The Common Stock of the Company is quoted on the Nasdaq National Market
under the symbol "RGEN". On June 24, 1997, the closing sale price of the Common
Stock was $1.1875 per share.

Investors should carefully consider the factors set forth under "Risk Factors."
See page 4.

                       -----------------------------------

THESE SECURITIES HAVE NOT BEEN APPROVED OR DISAPPROVED BY THE SECURITIES AND
EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION NOR HAS THE SECURITIES
AND EXCHANGE COMMISSION OR ANY STATE SECURITIES COMMISSION PASSED UPON THE
ACCURACY OR ADEQUACY OF THIS PROSPECTUS. ANY REPRESENTATION TO THE CONTRARY IS A
CRIMINAL OFFENSE.

                                 ---------------

No dealer, sales representative or other person has been authorized to give any
information or to make any representations in connection with this offering
other than those contained in this Prospectus and, if given or made, such
information or representations must not be relied upon as having been authorized
by the Company or the Selling Stockholders. This Prospectus does not constitute
an offer to sell or a solicitation of any offer to buy Common Stock by anyone in
any jurisdiction in which such an offer or solicitation is not authorized, or in
which the person making such an offer or solicitation is not qualified to do so,
or to any person whom it is unlawful to make such an offer or solicitation.
Neither the delivery of this Prospectus nor any sale made hereunder shall, under
any circumstances, create any implication that the information contained herein
is correct as of any date subsequent to its date.

                                 ---------------

   
                  The date of this Prospectus is July 8, 1997.
    





     This Prospectus contains certain statements of a forward-looking nature
relating to future events or the future financial performance of the Company.
Prospective investors are cautioned that such statements are only predictions
and that actual events or results may differ materially. In evaluating such
statements, prospective investors should specifically consider the various
factors identified in this Prospectus, including the matters set forth under the
caption "Risk Factors," which could cause actual results to differ materially
from those indicated by such forward-looking statements.

                             ADDITIONAL INFORMATION

     The Company is subject to the informational requirements of the Securities
Exchange Act of 1934, as amended (the "Exchange Act"), and in accordance
therewith files reports, proxy statements and other information with the
Securities and Exchange Commission (the "Commission"). Such reports, proxy
statements and other information may be inspected and copied at the public
reference facilities maintained by the Commission at Room 1024, Judiciary Plaza,
450 Fifth Street, N.W., Washington, D.C. 20549; 500 West Madison Street,
Chicago, IL 60621; and Seven World Trade Center, New York, NY 10048. Copies of
such material can be obtained from the Reference Section of the Commission at
Judiciary Plaza, 450 Fifth Street, N.W., Washington, D.C. 20549 at prescribed
rates. The Company's Common Stock is traded on the Nasdaq National Market, and
such reports, proxy statements and other information may be inspected at the
offices of Nasdaq Operations, 1735 K Street, N.W., Washington, D.C. 20006.
Additionally, the Commission maintains a Web site that contains reports, proxy
and information statements and other information regarding the Company at
http://www.sec.gov.

     The Company has filed with the Commission a Registration Statement on Form
S-3 (including all amendments, exhibits and schedules thereto, the "Registration
Statement") under the Securities Act of 1933, as amended (the "Securities Act"),
with respect to the Common Stock offered hereby. As permitted by the rules and
regulations of the Commission, this Prospectus omits certain information
contained in the Registration Statement. For further information with respect to
the Company and the Common Stock offered hereby, reference is hereby made to the
Registration Statement and to the exhibits and schedules filed therewith.
Statements contained in this Prospectus regarding the contents of any agreement
or other document filed as an exhibit to the Registration Statement are not
necessarily complete, and in each instance reference is made to the copy of such
agreement filed as an exhibit to the Registration Statement, each such statement
being qualified in all respects by such reference. The Registration Statement,
including the exhibits and schedules thereto, may be inspected at the public
reference facilities maintained by the Commission as described above, and copies
of all or any part thereof may be obtained from such facilities upon payment of
the prescribed fees.

                 INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

     The following documents, heretofore filed by the Company with the
Commission pursuant to the Exchange Act, are incorporated by reference in this
Prospectus:

     (i) Annual Report on Form 10-K for the fiscal year ended March 31, 1997,
including portions of the Company's Proxy Statement dated June 19, 1997 for its
Annual Meeting of Stockholders to be held on July 24, 1997; and

     (ii) The section entitled "Description of Registrant's Securities to be
Registered" contained in the Company's Registration Statement on Form 8-A filed
under the Exchange Act and declared effective on May 28, 1986, including any
amendment or reports filed for the purpose of updating such description.

     Each document subsequently filed by the Company pursuant to Section 13(a),
13(c), 14 or 15(d) of the Exchange Act, prior to the termination of the offering
of the shares of Common Stock made hereby, shall be deemed to be incorporated by
reference in this Prospectus and to be a part hereof from the date of filing of
such document. The Company will provide without charge to each person, including
any beneficial owner, to whom a copy of this Prospectus is delivered, upon the
written or oral request of any such person, a copy of any document described
above (other than exhibits). Requests for such copies should be directed to
Daniel P. Witt, Secretary, Repligen Corporation, 117 Fourth Avenue, Needham,
Massachusetts 02194; telephone (617) 449-9560.

     Any statement contained herein or in a document incorporated or deemed to
be incorporated herein by reference shall be deemed to be modified or superseded
for purposes of this Prospectus to the extent that a statement contained herein
or in any subsequently filed document that is incorporated by reference herein
modifies or supersedes such statement. Any such statement so modified or
superseded shall not be deemed, except as so modified or superseded, to
constitute a part of this Prospectus.


                                      -2-


                                   THE COMPANY

     Repligen Corporation ("Repligen" or the "Company") redirected its focus in
March of 1996 from the clinical development of biological products to the
development of enabling technology for the discovery of new drugs. The Company
is developing technology to increase the efficiency of the process by which new
drug candidates are identified. The Company believes that the pharmaceutical
industry has undergone a significant consolidation which has increased the use
of "out-sourcing" in all aspects of the pharmaceuticals development business.
Repligen believes that there is an opportunity to supply high value products
which facilitate the manufacture of pharmaceuticals. These technologies include
rapid methods for the synthesis of chemical compound libraries, novel detection
technology for identifying active compounds in drug screening and specific
screening assays based on defined biological targets. In selected therapeutic
areas, Repligen is applying its technology to the discovery of proprietary drug
leads capable of blocking biologically important protein-protein and
protein-carbohydrate interactions.

     Repligen also manufactures and markets a line of products for the
production of monoclonal antibodies intended for human clinical use. These
products are based on a recombinant form of Protein A for which Repligen holds
patents in the United States and major foreign markets. In addition, the Company
is seeking to license to third parties certain intellectual property and other
assets of the Company pertaining to its earlier research and clinical
development programs.

     Repligen also intends to leverage its existing technology base by seeking
to establish milestone and royalty-based collaborations with pharmaceutical
development partners. The Company will attempt to initiate multiple drug
discovery collaborations with pharmaceutical and biotechnology companies to
provide current revenue and the opportunity for future milestone or royalty
income.

                                ---------------

     The Company originally was incorporated in Delaware in 1981. The Company's
principal executive offices are located at 117 Fourth Avenue, Needham,
Massachusetts 02194, and its telephone number is (617) 449-9560. As used in this
Prospectus, the terms "Repligen" and the "Company" refer to Repligen
Corporation, unless the context otherwise requires.




                                      -3-


                                  RISK FACTORS


     In addition to the other information in this Prospectus, the following
factors should be considered carefully in evaluating an investment in the shares
of Common Stock offered hereby.

     Additional Financing Requirements. The Company believes additional
long-term financing will be required for the development of its drug discovery
programs and bioprocessing products business and to support its future
operations and capital expenditures. The Company from time to time may raise
additional capital through equity or debt financing or by entering into
corporate partnering arrangements; however, there can be no assurances that this
funding will be made available or that terms acceptable to the Company will be
reached.

     Potential Fluctuations in Operating Results. The Company's operating
results may vary significantly from quarter to quarter or year to year,
depending on factors such as the timing of increased research and development
and sales and marketing expenses, the timing and size of product orders, the
introduction of new products by the Company and the capital resources of the
Company's customers. The Company's current and planned expense levels are based
in part on its expectations as to future revenue. Consequently, revenue or
profits may vary significantly from quarter to quarter or year to year and
revenue or profits in any period will not necessarily be predictive of results
in subsequent periods. There can be no assurance that the Company will achieve
or maintain profitability or that its revenue growth can be sustained in the
future.

     Dependence on Key Personnel. The Company is highly dependent on the members
of its management and scientific staff, the loss of whom could have a material
adverse effect on the Company. In addition, the Company believes that its future
success will depend in large part upon its ability to attract and retain highly
skilled scientific, managerial and marketing personnel. The Company faces
significant competition for such personnel from other companies, research and
academic institutions, government entities and other organizations. There can be
no assurance that the Company will be successful in hiring or retaining the
personnel it requires for continued growth. The failure to hire and retain such
personnel could materially adversely affect the Company's prospects.

     The Company's success will depend, in part, on attracting and maintaining
key employees, successful integration of recent acquisitions, continued support
from current customers, development of new customers and successful enforcement
of the Company's patent and proprietary rights.

     Intense Competition and Risk of Technological Obsolescence. The Company
encounters, and expects to continue to encounter, intense competition in the
sale of its current and future products. There can be no assurance that
developments by others will not render the Company's products or technologies
obsolete or non-competitive. Many of the Company's competitors and potential
competitors have substantially greater resources, manufacturing and marketing
capabilities, research and development staff and production facilities than
those of the Company.


                                      -4-



                                USE OF PROCEEDS

     The Company will not receive any of the proceeds from the sale of the
Shares by the Selling Stockholders.

                              SELLING STOCKHOLDERS

         The following table sets forth certain  information as of June 20, 1997
with respect to the Shares held by the Selling  Stockholders.  The Shares may be
offered  from  time  to  time  by  the  Selling   Stockholders.   See  "Plan  of
Distribution."



   
                           Shares Beneficially Owned                        Shares Beneficially Owned
                             Prior to Offering (1)       Shares Offered       After Offering (1) (2)
                             --------------------       Pursuant to this     ----------------------
                              Number   Percent            Prospectus          Number      Percent
                              ------   -------            ----------          ------      -------
                                                                            
Globus Growth Group, Inc.      100,468       *             100,468                 0         *
                              
                              
Daniel P. Witt (3)             107,668       *              89,668            18,000         *
                              
                              
James R. Rusche (4)            121,668       *              89,668            32,000         *
                              
                              
Walter C. Herlihy (5)          149,668       *              89,668            60,000         *
                              
Imperial Cancer Research      
Technology Limited              64,000       *              64,000                 0         *
                              
                              
Mark B. Fisher                  39,800       *              57,800                 0         *
                              
                              
Ramesh L. Ratan (6)             16,892       *              16,892                 0         *
                              
                              
Ronald J. Frank                 16,000       *              16,000                 0         *
                              
                              
Leonard P. Shaykin              13,334       *              13,334                 0         *
                              
Delaware Charter Guarantee    
& Trust Co., Trustee FBO      
Mark B. Fisher                  13,333       *              13,333                 0         *
                              
Nelson Broms                     8,000       *               8,000                 0         *


                                      -5-

                              

                           Shares Beneficially Owned                        Shares Beneficially Owned
                             Prior to Offering (1)       Shares Offered       After Offering (1) (2)
                             --------------------       Pursuant to this     ----------------------
                              Number   Percent            Prospectus          Number      Percent
                              ------   -------            ----------          ------      -------
                                                                            
P&E Ventures                     8,000       *               8,000                 0         *
                              
                              
S. Leslie Misrock                8,000       *               8,000                 0         *
                              
                              
Klaus Biemann (7)               40,500       *               6,500            34,000         *
                              
                              
Paul DeStefano                   6,400       *               6,400                 0         *
                              
                              
Professor John Gallagher         5,900       *               5,900                 0         *
                              
                              
Ulf Lindahl, M.D.                5,900       *               5,900                 0         *
                              
                              
Lawrence  J. Bottecelli          3,750       *               3,750                 0         *
                              
                              
Robert Rosenberg                 3,750       *               3,750                 0         *
                              
                              
Peter G. Landsbury. Jr.          3,750       *               3,750                 0         *
                              
                              
Donald W. Kufe                   3,750       *               3,750                 0         *
                              
                              
Cy A. Stein                      3,750       *               3,750                 0         *
                              
                              
Dr. Peter Nickel                 3,750       *               3,750                 0         *
                              
                              
Marc S. Collette (8)            13,500       *               3,500            10,000         *
                              
                              
Scott D. Putney (9)             13,500       *               3,500            10,000         *
                              
                              
Mitchell P. Fink (10)           23,500       *               3,500            20,000         *
                              


                                      -6-



                           Shares Beneficially Owned                        Shares Beneficially Owned
                             Prior to Offering (1)       Shares Offered       After Offering (1) (2)
                             --------------------       Pursuant to this     ----------------------
                              Number   Percent            Prospectus          Number      Percent
                              ------   -------            ----------          ------      -------
                                                                            
William S. Doyle as           
custodian for William            2,667       *               2,667                 0         *
Elliott Doyle                 
                              
Manice Family Investment      
Club                             2,667       *               2,667                 0         *
                              
Laura Lees Whitehouse (11)       8,932       *               1,432             7,500         *
                                                                                             
                              
Arthur D. Lander                 1,400       *               1,400                 0         *
                              
                              
Judah Folkman                    1,400       *               1,400                 0         *
                              
                              
James D. Quirk                     750       *                 750                 0         *

Shane Sorenson                   8,000       *               8,000                 0         *

Carol Sorenson                   8,000       *               8,000                 0         *

Jill Sorenson                    2,000       *               2,000                 0         *


- ---------------               
  *  Represents less than 1% of the outstanding shares.
 (1) The number of shares of Common Stock deemed outstanding includes 16,001,875
     shares outstanding as of June 20, 1997 and shares issuable pursuant to
     outstanding options that may be exercised within sixty days after June 20,
     1997 ("presently exercisable stock options").
 (2) Assumes that the Selling Stockholders will sell all of the Shares
     registered hereunder. The Stockholders may sell all or part of their Shares
     pursuant to this Prospectus.
 (3) Includes 12,000 shares beneficially owned by Dr. Witt which may be acquired
     within sixty days pursuant to presently exercisable stock options. Dr. Witt
     serves as the Vice President of Business Development of the Company.
 (4) Includes 12,000 shares beneficially owned by Dr. Rusche which may be
     acquired within sixty days pursuant to presently exercisable stock options.
     Dr. Rusche serves as the Vice President of Research and Development of the
     Company.
 (5) Includes 20,000 shares beneficially owned by Dr. Herlihy which may be
     acquired within sixty days pursuant to presently exercisable stock options.
     Dr. Herlihy serves as the President and Chief Executive Officer of the
     Company.
 (6) Mr. Ratan served in various positions with the Company, including Vice
     President Finance and Administration, Treasurer and Chief Financial Officer
     of the Company, during the period from November 1986 through January 1995.
 (7) Includes 20,000 shares beneficially owned by Dr. Biemann which may be
     acquired within sixty days pursuant to presently exercisable stock options.
 (8) Includes 10,000 shares beneficially owned by Mr. Collette which may be
     acquired within sixty days pursuant to presently exercisable stock options.
 (9) Includes 10,000 shares beneficially owned by Mr. Putney which may be
     acquired within sixty days pursuant to presently exercisable stock options.
    


                                      -7-


(10) Includes 20,000 shares beneficially owned by Dr. Fink which may be acquired
     within sixty days pursuant to presently exercisable stock options.
(11) Includes 2,000 shares beneficially owned by Ms. Whitehouse which may be
     acquired within sixty days pursuant to presently exercisable stock options.

     Except as described above, to the best of the Company's knowledge, none of
the Selling Stockholders had any material relationship with the Company or any
of its affiliates within the three year period ending on the date of this
Prospectus.

     Certain of the Selling Stockholders acquired an aggregate of 399,243 Shares
on December 30, 1996 and March 31, 1997 in connection with the exchange by the
Company of all of the outstanding capital stock of ProsCure, Inc., a
partly-owned subsidiary of the Company ("ProsCure"), for Common Stock of the
Company pursuant to the terms and conditions of the exchange offer (the
"Exchange Offer"), by and between the Company, and each holder of capital stock,
including warrants, preferred stock and common stock, of ProsCure (the
"Exchange"). Others of the Selling Stockholders received an aggregate of 243,604
shares of Repligen Common Stock pursuant to a Plan of Reorganization and
Agreement of Merger dated March 14, 1996 by and between Repligen and Glycan
Pharmaceuticals, Inc. (the "Merger Agreement") pursuant to which Glycan
Pharmaceuticals, Inc. ("Glycan") was merged into a wholly owned subsidiary of
Repligen, Repligen Acquisition Corp., in the form of a reverse triangular
merger.

     The Selling Stockholders have represented to the Company that they acquired
the Shares as principal for their own accounts for investment and not with a
view to, or for sale in connection with, any distribution of the Shares in
contravention of the Securities Act or any other applicable securities
legislation. In recognition of the fact, however, that the Selling Stockholders
may want to be able to sell the Shares when they consider it appropriate, in
connection with the Purchase Agreement, the Company agreed to file the
Registration Statement with the Commission to effect the registration of the
resale of the Shares under the Securities Act and to use reasonable efforts to
keep the Registration Statement effective until the earliest of (a) such time as
all of the Shares have been sold pursuant to the Registration Statement, (b)
March 31, 2000 and (c) the date that Rule 144(k) under the Securities Act (or
successor provision) is available for the resale of the Shares.

                              PLAN OF DISTRIBUTION

     The Shares offered hereby may be sold from time to time by the Selling
Stockholders for their own accounts. The Company is responsible for the expenses
incurred in connection with the registration of the Shares, except as otherwise
set forth in the Exchange Offer or the Merger Agreement. The Company will not
receive any of the proceeds from this offering. The Selling Stockholders will
pay or assume brokerage commissions or other charges and expenses incurred in
the sale of the Shares.


     In addition, the Company has agreed to indemnify the Selling Stockholders
against certain liabilities, including liabilities under the Securities Act.


     The distribution of the Shares by the Selling Stockholders is not subject
to any underwriting agreement. The Shares covered by this Prospectus may be sold
by the Selling Stockholders or by pledges, donees, transferees or other
successors in interest. The Shares offered by the Selling Stockholders may be
sold from time to time in transactions on the Nasdaq National Market, in
negotiated transactions, through the writing of options on the Shares, or a
combination of such methods of sale, at fixed prices that may be 




                                      -8-


changed, at market prices prevailing at the time of sale, at prices relating to
such prevailing market prices or at negotiated prices. In addition, the Selling
Stockholders may sell their Shares covered by this Prospectus through customary
brokerage channels, either through broker-dealers acting as agents or brokers,
or through broker-dealers acting as principals, who may then resell the Shares,
or at private sale or otherwise, at market prices prevailing at the time of
sale, at prices related to such prevailing market prices or at negotiated
prices. The Selling Stockholders may effect such transactions by selling Shares
to or through broker-dealers, and such broker-dealers may receive compensation
in the form of discounts, concessions, commissions, or fees from the Selling
Stockholders and/or purchasers of the Shares for whom such broker-dealers may
act as agent or to whom they sell as principal, or both (which compensation to a
particular broker-dealer might be in excess of customary commissions). Any
broker-dealers that participate with the Selling Stockholders in the
distribution of Shares may be deemed to be underwriters and any commissions
received by them and any profit on the resale of Shares placed by them might be
deemed to be underwriting discounts and commissions within the meaning of the
Securities Act, in connection with such sales.

     Any shares covered by the Prospectus that qualify for sale pursuant to Rule
144 under the Securities Act may be sold under Rule 144 rather than pursuant to
this Prospectus.

     Since the Selling Stockholders are not restricted as to the price or prices
at which they may sell their Shares, sales of such Shares at less than the
market prices may depress the market price of the Company's Common Stock.

     Boston EquiServ L.P., 150 Royall Street, Canton, MA 02021, is the transfer
agent for the Company's Common Stock.

                                  LEGAL MATTERS

     The validity of the shares of Common Stock offered hereby will be passed
upon for the Company and the Selling Stockholders by Testa, Hurwitz & Thibeault,
LLP, Boston, Massachusetts.

                                     EXPERTS

     The financial statements and financial statement schedule of the Company as
of March 31, 1997 and 1996 and for each of the three years in the period ended
March 31, 1997, incorporated by reference in this Prospectus and in the
Registration Statement have been audited by Arthur Andersen LLP, independent
public accountants, as set forth in their report thereon incorporated herein,
and are included in reliance upon such report incorporated herein given upon the
authority of such firm as experts in auditing and accounting.


                                      -9-



================================================================================

No dealer, sales representative or any other person has been authorized to give
any information or to make any representations in connection with this offering
other than those contained in this prospectus, and, if given or made, such
information or representations must not be relied upon as having been authorized
by the company, any of the selling stockholders or any of the underwriters. This
prospectus does not constitute an offer to sell, or a solicitation of an offer
to buy, any securities other than the registered securities to which it relates
or an offer to, or a solicitation of, any person in any jurisdiction where such
offer or solicitation would be unlawful. Neither the delivery of this prospectus
nor any sale made hereunder shall, under any circumstances, create any
implication that there has been no change in the affairs of the company since
the date hereof or that the information contained herein is correct as of any
time subsequent to the date hereof.

                            -------------------------

                                TABLE OF CONTENTS


                                                                       PAGE
                                                                       ----
Additional Information............................................      2
Incorporation of Certain Documents                          
 by Reference.....................................................      2
The Company.......................................................      3
Risk Factors......................................................      4
Use of Proceeds...................................................      5
Selling Stockholders..............................................      5
Plan of Distribution..............................................      8
Legal Matters.....................................................      9
Experts...........................................................      9
                                          
================================================================================



                                 642,847 Shares



                              REPLIGEN CORPORATION


                                  Common Stock





                             -----------------------

                                   PROSPECTUS


   
                                  July 8, 1997
    

                            ------------------------










===============================================================================