content: <PAGE>   1
        As filed with the Securities and Exchange Commission on June 25, 1996
  
                                                        REGISTRATION NO. 333-
  
  
                         SECURITIES AND EXCHANGE COMMISSION
                               Washington, D. C. 20549
  
                                ---------------------
  
                                      FORM S-8
  
                            REGISTRATION STATEMENT UNDER
                             THE SECURITIES ACT OF 1933
  
                                ---------------------
  
                            GELTEX PHARMACEUTICALS, INC.
               (Exact name of registrant as specified in its charter)
  
  
            DELAWARE                                           04-3136767
  (State or other jurisdiction                              (I.R.S. Employer 
        of incorporation)                                  Identification No.)
  
           303 BEAR HILL ROAD, WALTHAM, MASSACHUSETTS 02154 (617) 290-5888
     (Address and telephone number of registrant's principal executive offices)
                                ---------------------
  
                           1995 DIRECTOR STOCK OPTION PLAN
                              (Full Title of the Plan)
  
                MARK SKALETSKY, PRESIDENT AND CHIEF EXECUTIVE OFFICER
                            GelTex Pharmaceuticals, Inc.
                                 303 Bear Hill Road
                            Waltham, Massachusetts 02154
                                   (617) 290-5888
              (Name, address and telephone number of agent for service)
  
                                   with copies to:
  
                                PETER WIRTH, ESQUIRE
                                 Palmer & Dodge LLP
                                  One Beacon Street
                             Boston, Massachusetts 02108
                                   (617) 573-0100
                                ---------------------
  
  
  
                           CALCULATION OF REGISTRATION FEE
  
  <TABLE>
  <CAPTION>
  - -------------------------------------------------------------------------------------------------------------------------------
  Title of each class of securities to     Amount to be              Proposed             Proposed maximum          Amount of
            be registered                   registered           maximum offering        aggregate offering      registration fee
                                                                  price per share              price
  - -------------------------------------------------------------------------------------------------------------------------------
  <S>                                    <C>                        <C>                    <C>                       <C>    
  Common Stock, $0.01 par value          52,000 shares(1)            $11.25(2)             $585,000.00(2)            $202.00
  - -------------------------------------------------------------------------------------------------------------------------------
  Common Stock, $0.01 par value          23,000 shares              $21.125(3)             $485,875.00(3)            $168.00
  - -------------------------------------------------------------------------------------------------------------------------------
  </TABLE>
  
  (1)  Shares subject to outstanding options.
  (2)  Computed in accordance with Rule 457(h)(1) based on the price per share at
       which currently outstanding options may be exercised.
  (3)  Estimated solely for the purpose of determining the registration fee and
       computed pursuant to Rule 457(h) based upon the average of the high and low
       sale prices on June 19, 1996 as reported by the Nasdaq National Market
       System.
  
                                    Page 1 of 23
                           Exhibit Index appears at Page 8
  <PAGE>   2
                                       PART II
                 INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
  
  
  Item 3.  Incorporation of Documents by Reference.
  
           The following documents filed with the Securities and Exchange
  Commission (the "Commission") are incorporated herein by reference:
  
           (a)  The Registrant's Annual Report on Form 10-K for the fiscal year
  ended December 31, 1995 (File No. 0-26872) filed with the Commission on March
  29, 1996.
  
           (b)  All other reports of the registrant filed pursuant to Section 
  13(a) or 15(d) of the Securities Exchange Act of 1934, as amended (the "Exchange
  Act"), since the end of the fiscal year covered by the annual report referred to
  in (a) above.
  
           (c)  The description of the Registrant's Common Stock contained in its
  Registration Statement on Form 8-A (File No. 0-26872) filed with the Commission
  on September 26, 1995, as amended on October 12, 1995, including any amendment
  or report filed hereafter for the purpose of updating such description.
  
           All documents filed after the date of this Registration Statement by
  the Registrant pursuant to Section 13(a), 13(d), 14 and 15(d) of the Exchange
  Act and prior to the filing of a post-effective amendment that indicates that
  all shares of Common Stock offered hereunder have been sold or which deregisters
  all shares of Common Stock remaining unsold shall be deemed to be incorporated
  by reference herein and to be a part hereof from the date of the filing of such
  reports and documents.
  
  Item 4.  Description of Securities.
  
           Not applicable.
  
  Item 5.  Interests of Named Experts and Counsel.
  
           The validity of the Common Stock offered hereby will be passed upon for
  the Registrant by Palmer & Dodge LLP, Boston, Massachusetts. Peter Wirth, a
  partner of Palmer & Dodge LLP, is Secretary of the Registrant.
  
  Item 6. Indemnification of Directors and Officers
  
           Section 145 of the Delaware General Corporation Law permits the
  Registrant to indemnify directors, officers, employees and agents of the
  Registrant against actual and reasonable expenses (including attorneys' fees)
  incurred by them in connection with any action, suit or proceeding brought
  against them by reason of their status or service as a director, officer,
  employee or agent by or on behalf of the Registrant, and against expenses
  (including attorneys' fees), judgments, fines and settlements actually and
  reasonably incurred by him in connection with any such action, suit or
  proceeding, if (i) he acted in good faith and in a manner he reasonably believed
  to be in or not opposed to the best interests of the Registrant, and (ii) in the
  case of a criminal proceeding, he had no reasonable cause to believe his
  
  
                                        - 2 -
  <PAGE>   3
  conduct was unlawful. Except as ordered by a court, no indemnification shall be
  made in connection with any proceeding brought by or in the right of the
  corporation where the person involved is adjudged to be liable to the
  Registrant.
  
           Article EIGHTH of the Registrant's Restated Certificate of
  Incorporation provides that a director shall not be personally liable to the
  Registrant or its stockholders for monetary damages for breach of fiduciary duty
  as a director, except to the extent that elimination or limitation of liability
  is not permitted under the Delaware General Corporation Law as in effect when
  such liability is determined.
  
           Article NINTH of the Registrant's Restated Certificate of Incorporation
  provides that the Registrant shall, to the fullest extent permitted by the
  General Corporation Law of the State of Delaware, as amended from time to time,
  indemnify each person who was or is a party or is threatened to be made a party
  to any threatened, pending or completed action, suit or proceeding whether
  civil, criminal, administrative or investigative, by reason of the fact that he
  is or was, or has agreed to become a director or officer of the Registrant, or
  is or was serving, or has agreed to serve at the request of the Registrant as a
  director, officer or trustee of, or in a similar capacity with, another
  corporation, partnership, joint venture, trust or other enterprise. The
  indemnification provided for in Article NINTH is expressly not exclusive of any
  other rights to which those seeking indemnification may be entitled under any
  law, agreement or vote of stockholders or disinterested directors or otherwise,
  and shall inure to the benefit of the heirs, executors and administrators of
  such persons. Article NINTH further permits the Board of Directors to authorize
  the grant of indemnification rights to other employees and agents of the
  Registrant and such rights may be equivalent to, or greater or less than, those
  set forth in Article NINTH.
  
           Article V, Section 1 of the Registrant's By-Laws provides that the
  Registrant shall have the power to purchase and maintain insurance on behalf of
  any person who is or was a director, officer, employee or agent of the
  Registrant, or is or was serving at the request of the Registrant as a director,
  officer, employee or agent of another corporation, partnership, joint venture,
  trust or other enterprise against any liability asserted against such person and
  incurred by such person in any such capacity or arising out of such person's
  status as such.
  
           The Registrant maintains insurance for directors and officers and
  expects to enter into agreements with certain officers and directors affirming
  the Registrant's obligation to indemnify them to the fullest extent permitted by
  law and providing various other protections.
  
  Item 7. Exemption from Registration Claimed.
  
           Not applicable.
  
  
                                        - 3 -
  <PAGE>   4
  Item 8. Exhibits.
  
  <TABLE>
  <CAPTION>
     Exhibit Number                                    Description
     --------------                                    -----------
  
  <S>                  <C>                              
          4.1          Restated Certificate of Incorporation of the Registrant.
  
          4.2          Amended and Restated By-laws of the Registrant.  Filed as Exhibit 3.3 to
                       the Company's Annual Report on Form 10-K for the fiscal year ended
                       December 31, 1995 and incorporated herein by reference.
  
          4.3          Rights Agreement dated as of March 1, 1996 between the Company and
                       American Stock Transfer & Trust Company.  Filed as Exhibit 1 to the
                       Company's Registration Statement on Form 8-A dated March 1, 1996 and
                       incorporated herein by reference.
  
          5.1          Opinion of Palmer & Dodge LLP as to the legality of the securities
                       registered hereunder.
  
         23.1          Consent of Ernst & Young LLP, independent auditors.
  
         23.2          Consent of Palmer & Dodge LLP (contained in Opinion of Palmer &
                       Dodge LLP, filed as Exhibit 5.1 hereto).
  
         24.1          Power of Attorney (set forth on the signature page to this Registration
                       Statement).
  
         24.2          Certified resolution of the Board of Directors authorizing Power of
                       Attorney.
  
         99.1          1995 Director Stock Option Plan.  Filed as Exhibit 10.22 to the
                       Company's Annual Report on Form 10-K for the fiscal year ended
                       December 31, 1995 and incorporated herein by reference.
  
         99.2          Form of 1995 Director Stock Option Plan Nonstatutory Stock Option
                       Certificate.
  </TABLE>
  
  Item 9.  Undertakings.
  
           (a)  The undersigned Registrant hereby undertakes:
  
                (1)  To file, during any period in which offers or sales are
  being made, a post-effective amendment to this registration statement:
  
                     (i)  To include any prospectus required by Section 10(a)(3)
  of the Securities Act of 1933;
  
                    (ii)  To reflect in the prospectus any facts or events arising
  after the effective date of this Registration Statement (or the most recent
  post-effective amendment thereof) which, individually or in the aggregate,
  represents a fundamental change in the information set forth in this
  Registration Statement;
  
  
                                        - 4 -
  <PAGE>   5
                   (iii)  To include any material information with respect to the
  plan of distribution not previously disclosed in this Registration Statement or
  any material change to such information in this Registration Statement;
  
  provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not apply if the
  information required to be included in a post-effective amendment by those
  paragraphs is contained in periodic reports filed by the Registrant pursuant to
  Section 13 or Section 15(d) of the Securities Exchange Act of 1934 that are
  incorporated by reference in this Registration Statement.
  
                (2)  That, for the purpose of determining any liability under the
  Securities Act of 1933, each such post-effective amendment shall be deemed to be
  a new registration statement relating to the securities offered therein, and the
  offering of such securities at that time shall be deemed to be the initial bona
  fide offering thereof.
  
                (3)  To remove from registration by means of a post-effective
  amendment any of the securities being registered which remain unsold at the
  termination of the offering.
  
           (b)  The undersigned Registrant hereby undertakes that, for purposes of
  determining any liability under the Securities Act of 1933, each filing of the
  Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
  Securities Exchange Act of 1934 that is incorporated by reference in this
  Registration Statement shall be deemed to be a new registration statement
  relating to the securities offered therein, and the offering of such securities
  at that time shall be deemed to be the initial bona fide offering thereof.
  
           (c)  Insofar as indemnification for liabilities arising under the
  Securities Act of 1933 may be permitted to directors, officers and controlling
  persons of the Registrant pursuant to the provisions referred to in Item 6
  hereof, or otherwise, the Registrant has been advised that in the opinion of the
  Securities and Exchange Commission such indemnification is against public policy
  as expressed in the Act and is, therefore, unenforceable. In the event that a
  claim for indemnification against such liabilities (other than the payment by
  the Registrant of expenses incurred or paid by a director, officer or
  controlling person of the registrant in the successful defense of any action,
  suit or proceeding) is asserted by such director, officer or controlling person
  in connection with the securities being registered, the Registrant will, unless
  in the opinion of its counsel the matter has been settled by controlling
  precedent, submit to a court of appropriate jurisdiction the question whether
  such indemnification by it is against public policy as expressed in the Act and
  will be governed by the final adjudication of such issue.
  
  
                                        - 5 -
  <PAGE>   6
                                     SIGNATURES
  
  
           Pursuant to the requirements of the Securities Act of 1933, the
  Registrant certifies that it has reasonable grounds to believe that it meets all
  of the requirements for filing on Form S-8 and has duly caused this Registration
  Statement to be signed on its behalf by the undersigned, thereunto duly
  authorized, in the City of Waltham, State of Massachusetts, on this 25th day of
  June, 1996.
  
                                    GELTEX PHARMACEUTICALS, INC.
  
  
  
                                    By: /s/ Mark Skaletsky
                                        ------------------------------------------
                                         Mark Skaletsky
                                         President and Chief Executive Officer
  
                                  POWER OF ATTORNEY
  
           We, the undersigned officers and directors of GelTex Pharmaceuticals,
  Inc. hereby severally constitute and appoint Mark Skaletsky and Peter Wirth, and
  each of them singly, our true and lawful attorneys-in-fact, with full power to
  them in any and all capacities, to sign any and all amendments to this
  Registration Statement on Form S-8 including any post-effective amendments
  thereto, and to file the same, with exhibits thereto and other documents in
  connection therewith, with the Securities and Exchange Commission, hereby
  ratifying and confirming all that each of said attorneys-in-fact may do or cause
  to be done by virtue hereof.
  
           Pursuant to the requirements of the Securities Act of 1933, this
  Registration Statement has been signed below by the following persons in the
  capacities and on the dates indicated:
  
  <TABLE>
  <CAPTION>
         SIGNATURE                    TITLE                                  DATE
         ---------                    -----                                  ---- 
  
  <S>                                 <C>                                    <C> 
  /s/ Mark Skaletsky                  President, Chief Executive             June 25, 1996
  - -----------------------------       Officer and Treasurer                
  Mark Skaletsky                      (Principal Executive                 
                                      Officer, Principal Financial Officer 
                                      and Principal Accounting Officer)    
                                      
  
  /s/ Robert J. Carpenter             Chairman of the Board                  June 25, 1996
  - -----------------------------       and Director 
  Robert J. Carpenter                 
  
  /s/ Ernest Parizeau                 Director                               June 25, 1996
  - -----------------------------
  Ernest Parizeau
  </TABLE>
  
  
                                        - 6 -
  <PAGE>   7
  <TABLE>
  <CAPTION>
         SIGNATURE                    TITLE                      DATE
         ---------                    -----                      ---- 
  
  <S>                                 <C>                        <C> 
  /s/ Barbara A. Piette               Director                   June 25, 1996
  - -----------------------------
  Barbara A. Piette
  
  /s/ James Tananbaum                 Director                   June 25, 1996
  - -----------------------------
  James Tananbaum
  
  /s/ Henri A. Termeer                Director                   June 25, 1996
  - -----------------------------
  Henri A. Termeer
  
  /s/ Jesse Treu                      Director                   June 25, 1996
  - -----------------------------
  Jesse Treu
  
  /s/ George Whitesides               Director                   June 25, 1996
  - -----------------------------
  George Whitesides
  </TABLE>
  
  
                                        - 7 -
  <PAGE>   8
                                    EXHIBIT INDEX
  
  
  <TABLE>
  <CAPTION>
  Exhibit Number                               Description                                       Page Number
  - --------------                               -----------                                       -----------
  
  <S>                   <C>                                                                      <C>
        4.1             Restated Certificate of Incorporation of the Registrant.                      9
  
        4.2             Amended and Restated By-laws of the Registrant.                               *
                        Filed as Exhibit 3.3 to the Company's Annual Report
                        on Form 10-K for the fiscal year ended December 31,
                        1995.
  
        4.3             Rights Agreement dated as of March 1, 1996 between                            *
                        the Company and American Stock Transfer & Trust
                        Company.  Filed as Exhibit 1 to the Company's
                        Registration Statement on Form 8-A dated March 1,
                        1996.
  
        5.1             Opinion of Palmer & Dodge LLP as to the legality of                          19
                        the securities registered hereunder.
  
       23.1             Consent of Ernst & Young LLP, independent auditors.                          20
  
       23.2             Consent of Palmer & Dodge LLP (contained in                                  --
                        Opinion of Palmer & Dodge LLP, filed as Exhibit 5.1
                        hereto).
  
       24.1             Power of Attorney (set forth on the signature page to                        --
                        this Registration Statement).
  
       24.2             Certified resolution of the Board of Directors                               21
                        authorizing Power of Attorney.
  
       99.1             1995 Director Stock Option Plan.  Filed as Exhibit                            *
                        10.22 to the Company's Annual Report on Form 10-K
                        for the fiscal year ended December 31, 1995.
  
       99.2             Form of 1995 Director Stock Option Plan Nonstatutory                         22
                        Stock Option Certificate.
  </TABLE>
  
  
  
  - ----------------------------
  
  *  Incorporated herein by reference.
  
  
                                        - 8 -
metadata_documents: [{"type": "S-8", "sequence": "1", "description": "GELTEX PHARMACEUTICALS FORM S-8", "secsgml_size_bytes": 21094}]
metadata_filer: {"company-data": {"conformed-name": "GELTEX PHARMACEUTICALS INC", "cik": "0001001425", "assigned-sic": "2834", "irs-number": "043136767", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-06779", "film-number": "96585430"}, "business-address": {"street1": "303 BEAR HILL RD", "city": "WALTHAM", "state": "MA", "zip": "02154", "phone": "6172905888"}, "mail-address": {"street1": "303 BEAR HILL RD", "city": "WALTHAM", "state": "MA", "zip": "02154"}}
text: 1
        As filed with the Securities and Exchange Commission on June 25, 1996
  
                                                        REGISTRATION NO. 333-
  
                         SECURITIES AND EXCHANGE COMMISSION
                               Washington, D. C. 20549
  
                                ---------------------
  
                                      FORM S-8
  
                            REGISTRATION STATEMENT UNDER
                             THE SECURITIES ACT OF 1933
  
                                ---------------------
  
                            GELTEX PHARMACEUTICALS, INC.
               (Exact name of registrant as specified in its charter)
  
            DELAWARE                                           04-3136767
  (State or other jurisdiction                              (I.R.S. Employer 
        of incorporation)                                  Identification No.)
  
           303 BEAR HILL ROAD, WALTHAM, MASSACHUSETTS 02154 (617) 290-5888
     (Address and telephone number of registrant's principal executive offices)
                                ---------------------
  
                           1995 DIRECTOR STOCK OPTION PLAN
                              (Full Title of the Plan)
  
                MARK SKALETSKY, PRESIDENT AND CHIEF EXECUTIVE OFFICER
                            GelTex Pharmaceuticals, Inc.
                                 303 Bear Hill Road
                            Waltham, Massachusetts 02154
                                   (617) 290-5888
              (Name, address and telephone number of agent for service)
  
                                   with copies to:
  
                                PETER WIRTH, ESQUIRE
                                 Palmer & Dodge LLP
                                  One Beacon Street
                             Boston, Massachusetts 02108
                                   (617) 573-0100
                                ---------------------
  
                           CALCULATION OF REGISTRATION FEE
  - -------------------------------------------------------------------------------------------------------------------------------
  Title of each class of securities to     Amount to be              Proposed             Proposed maximum          Amount of
            be registered                   registered           maximum offering        aggregate offering      registration fee
                                                                  price per share              price
  - -------------------------------------------------------------------------------------------------------------------------------
  Common Stock, $0.01 par value          52,000 shares(1)            $11.25(2)             $585,000.00(2)            $202.00
  - -------------------------------------------------------------------------------------------------------------------------------
  Common Stock, $0.01 par value          23,000 shares              $21.125(3)             $485,875.00(3)            $168.00
  - -------------------------------------------------------------------------------------------------------------------------------
  (1)  Shares subject to outstanding options.
  (2)  Computed in accordance with Rule 457(h)(1) based on the price per share at
       which currently outstanding options may be exercised.
  (3)  Estimated solely for the purpose of determining the registration fee and
       computed pursuant to Rule 457(h) based upon the average of the high and low
       sale prices on June 19, 1996 as reported by the Nasdaq National Market
       System.
  
                                    Page 1 of 23
                           Exhibit Index appears at Page 8
  2
                                       PART II
                 INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
  
  Item 3.  Incorporation of Documents by Reference.
  
           The following documents filed with the Securities and Exchange
  Commission (the "Commission") are incorporated herein by reference:
  
           (a)  The Registrant's Annual Report on Form 10-K for the fiscal year
  ended December 31, 1995 (File No. 0-26872) filed with the Commission on March
  29, 1996.
  
           (b)  All other reports of the registrant filed pursuant to Section 
  13(a) or 15(d) of the Securities Exchange Act of 1934, as amended (the "Exchange
  Act"), since the end of the fiscal year covered by the annual report referred to
  in (a) above.
  
           (c)  The description of the Registrant's Common Stock contained in its
  Registration Statement on Form 8-A (File No. 0-26872) filed with the Commission
  on September 26, 1995, as amended on October 12, 1995, including any amendment
  or report filed hereafter for the purpose of updating such description.
  
           All documents filed after the date of this Registration Statement by
  the Registrant pursuant to Section 13(a), 13(d), 14 and 15(d) of the Exchange
  Act and prior to the filing of a post-effective amendment that indicates that
  all shares of Common Stock offered hereunder have been sold or which deregisters
  all shares of Common Stock remaining unsold shall be deemed to be incorporated
  by reference herein and to be a part hereof from the date of the filing of such
  reports and documents.
  
  Item 4.  Description of Securities.
  
           Not applicable.
  
  Item 5.  Interests of Named Experts and Counsel.
  
           The validity of the Common Stock offered hereby will be passed upon for
  the Registrant by Palmer & Dodge LLP, Boston, Massachusetts. Peter Wirth, a
  partner of Palmer & Dodge LLP, is Secretary of the Registrant.
  
  Item 6. Indemnification of Directors and Officers
  
           Section 145 of the Delaware General Corporation Law permits the
  Registrant to indemnify directors, officers, employees and agents of the
  Registrant against actual and reasonable expenses (including attorneys' fees)
  incurred by them in connection with any action, suit or proceeding brought
  against them by reason of their status or service as a director, officer,
  employee or agent by or on behalf of the Registrant, and against expenses
  (including attorneys' fees), judgments, fines and settlements actually and
  reasonably incurred by him in connection with any such action, suit or
  proceeding, if (i) he acted in good faith and in a manner he reasonably believed
  to be in or not opposed to the best interests of the Registrant, and (ii) in the
  case of a criminal proceeding, he had no reasonable cause to believe his
  
                                        - 2 -
  3
  conduct was unlawful. Except as ordered by a court, no indemnification shall be
  made in connection with any proceeding brought by or in the right of the
  corporation where the person involved is adjudged to be liable to the
  Registrant.
  
           Article EIGHTH of the Registrant's Restated Certificate of
  Incorporation provides that a director shall not be personally liable to the
  Registrant or its stockholders for monetary damages for breach of fiduciary duty
  as a director, except to the extent that elimination or limitation of liability
  is not permitted under the Delaware General Corporation Law as in effect when
  such liability is determined.
  
           Article NINTH of the Registrant's Restated Certificate of Incorporation
  provides that the Registrant shall, to the fullest extent permitted by the
  General Corporation Law of the State of Delaware, as amended from time to time,
  indemnify each person who was or is a party or is threatened to be made a party
  to any threatened, pending or completed action, suit or proceeding whether
  civil, criminal, administrative or investigative, by reason of the fact that he
  is or was, or has agreed to become a director or officer of the Registrant, or
  is or was serving, or has agreed to serve at the request of the Registrant as a
  director, officer or trustee of, or in a similar capacity with, another
  corporation, partnership, joint venture, trust or other enterprise. The
  indemnification provided for in Article NINTH is expressly not exclusive of any
  other rights to which those seeking indemnification may be entitled under any
  law, agreement or vote of stockholders or disinterested directors or otherwise,
  and shall inure to the benefit of the heirs, executors and administrators of
  such persons. Article NINTH further permits the Board of Directors to authorize
  the grant of indemnification rights to other employees and agents of the
  Registrant and such rights may be equivalent to, or greater or less than, those
  set forth in Article NINTH.
  
           Article V, Section 1 of the Registrant's By-Laws provides that the
  Registrant shall have the power to purchase and maintain insurance on behalf of
  any person who is or was a director, officer, employee or agent of the
  Registrant, or is or was serving at the request of the Registrant as a director,
  officer, employee or agent of another corporation, partnership, joint venture,
  trust or other enterprise against any liability asserted against such person and
  incurred by such person in any such capacity or arising out of such person's
  status as such.
  
           The Registrant maintains insurance for directors and officers and
  expects to enter into agreements with certain officers and directors affirming
  the Registrant's obligation to indemnify them to the fullest extent permitted by
  law and providing various other protections.
  
  Item 7. Exemption from Registration Claimed.
  
           Not applicable.
  
                                        - 3 -
  4
  Item 8. Exhibits.
  Exhibit Number                                    Description
     --------------                                    -----------
  4.1          Restated Certificate of Incorporation of the Registrant.
  
          4.2          Amended and Restated By-laws of the Registrant.  Filed as Exhibit 3.3 to
                       the Company's Annual Report on Form 10-K for the fiscal year ended
                       December 31, 1995 and incorporated herein by reference.
  
          4.3          Rights Agreement dated as of March 1, 1996 between the Company and
                       American Stock Transfer & Trust Company.  Filed as Exhibit 1 to the
                       Company's Registration Statement on Form 8-A dated March 1, 1996 and
                       incorporated herein by reference.
  
          5.1          Opinion of Palmer & Dodge LLP as to the legality of the securities
                       registered hereunder.
  
         23.1          Consent of Ernst & Young LLP, independent auditors.
  
         23.2          Consent of Palmer & Dodge LLP (contained in Opinion of Palmer &
                       Dodge LLP, filed as Exhibit 5.1 hereto).
  
         24.1          Power of Attorney (set forth on the signature page to this Registration
                       Statement).
  
         24.2          Certified resolution of the Board of Directors authorizing Power of
                       Attorney.
  
         99.1          1995 Director Stock Option Plan.  Filed as Exhibit 10.22 to the
                       Company's Annual Report on Form 10-K for the fiscal year ended
                       December 31, 1995 and incorporated herein by reference.
  
         99.2          Form of 1995 Director Stock Option Plan Nonstatutory Stock Option
                       Certificate.
  Item 9.  Undertakings.
  
           (a)  The undersigned Registrant hereby undertakes:
  
                (1)  To file, during any period in which offers or sales are
  being made, a post-effective amendment to this registration statement:
  
                     (i)  To include any prospectus required by Section 10(a)(3)
  of the Securities Act of 1933;
  
                    (ii)  To reflect in the prospectus any facts or events arising
  after the effective date of this Registration Statement (or the most recent
  post-effective amendment thereof) which, individually or in the aggregate,
  represents a fundamental change in the information set forth in this
  Registration Statement;
  
                                        - 4 -
  5
                   (iii)  To include any material information with respect to the
  plan of distribution not previously disclosed in this Registration Statement or
  any material change to such information in this Registration Statement;
  
  provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) do not apply if the
  information required to be included in a post-effective amendment by those
  paragraphs is contained in periodic reports filed by the Registrant pursuant to
  Section 13 or Section 15(d) of the Securities Exchange Act of 1934 that are
  incorporated by reference in this Registration Statement.
  
                (2)  That, for the purpose of determining any liability under the
  Securities Act of 1933, each such post-effective amendment shall be deemed to be
  a new registration statement relating to the securities offered therein, and the
  offering of such securities at that time shall be deemed to be the initial bona
  fide offering thereof.
  
                (3)  To remove from registration by means of a post-effective
  amendment any of the securities being registered which remain unsold at the
  termination of the offering.
  
           (b)  The undersigned Registrant hereby undertakes that, for purposes of
  determining any liability under the Securities Act of 1933, each filing of the
  Registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
  Securities Exchange Act of 1934 that is incorporated by reference in this
  Registration Statement shall be deemed to be a new registration statement
  relating to the securities offered therein, and the offering of such securities
  at that time shall be deemed to be the initial bona fide offering thereof.
  
           (c)  Insofar as indemnification for liabilities arising under the
  Securities Act of 1933 may be permitted to directors, officers and controlling
  persons of the Registrant pursuant to the provisions referred to in Item 6
  hereof, or otherwise, the Registrant has been advised that in the opinion of the
  Securities and Exchange Commission such indemnification is against public policy
  as expressed in the Act and is, therefore, unenforceable. In the event that a
  claim for indemnification against such liabilities (other than the payment by
  the Registrant of expenses incurred or paid by a director, officer or
  controlling person of the registrant in the successful defense of any action,
  suit or proceeding) is asserted by such director, officer or controlling person
  in connection with the securities being registered, the Registrant will, unless
  in the opinion of its counsel the matter has been settled by controlling
  precedent, submit to a court of appropriate jurisdiction the question whether
  such indemnification by it is against public policy as expressed in the Act and
  will be governed by the final adjudication of such issue.
  
                                        - 5 -
  6
                                     SIGNATURES
  
           Pursuant to the requirements of the Securities Act of 1933, the
  Registrant certifies that it has reasonable grounds to believe that it meets all
  of the requirements for filing on Form S-8 and has duly caused this Registration
  Statement to be signed on its behalf by the undersigned, thereunto duly
  authorized, in the City of Waltham, State of Massachusetts, on this 25th day of
  June, 1996.
  
                                    GELTEX PHARMACEUTICALS, INC.
  
                                    By: /s/ Mark Skaletsky
                                        ------------------------------------------
                                         Mark Skaletsky
                                         President and Chief Executive Officer
  
                                  POWER OF ATTORNEY
  
           We, the undersigned officers and directors of GelTex Pharmaceuticals,
  Inc. hereby severally constitute and appoint Mark Skaletsky and Peter Wirth, and
  each of them singly, our true and lawful attorneys-in-fact, with full power to
  them in any and all capacities, to sign any and all amendments to this
  Registration Statement on Form S-8 including any post-effective amendments
  thereto, and to file the same, with exhibits thereto and other documents in
  connection therewith, with the Securities and Exchange Commission, hereby
  ratifying and confirming all that each of said attorneys-in-fact may do or cause
  to be done by virtue hereof.
  
           Pursuant to the requirements of the Securities Act of 1933, this
  Registration Statement has been signed below by the following persons in the
  capacities and on the dates indicated:
  SIGNATURE                    TITLE                                  DATE
         ---------                    -----                                  ----
  /s/ Mark Skaletsky                  President, Chief Executive             June 25, 1996
  - -----------------------------       Officer and Treasurer                
  Mark Skaletsky                      (Principal Executive                 
                                      Officer, Principal Financial Officer 
                                      and Principal Accounting Officer)    
                                      
  
  /s/ Robert J. Carpenter             Chairman of the Board                  June 25, 1996
  - -----------------------------       and Director 
  Robert J. Carpenter                 
  
  /s/ Ernest Parizeau                 Director                               June 25, 1996
  - -----------------------------
  Ernest Parizeau
  - 6 -
  7
  SIGNATURE                    TITLE                      DATE
         ---------                    -----                      ----
  /s/ Barbara A. Piette               Director                   June 25, 1996
  - -----------------------------
  Barbara A. Piette
  
  /s/ James Tananbaum                 Director                   June 25, 1996
  - -----------------------------
  James Tananbaum
  
  /s/ Henri A. Termeer                Director                   June 25, 1996
  - -----------------------------
  Henri A. Termeer
  
  /s/ Jesse Treu                      Director                   June 25, 1996
  - -----------------------------
  Jesse Treu
  
  /s/ George Whitesides               Director                   June 25, 1996
  - -----------------------------
  George Whitesides
  - 7 -
  8
                                    EXHIBIT INDEX
  Exhibit Number                               Description                                       Page Number
  - --------------                               -----------                                       -----------
  4.1             Restated Certificate of Incorporation of the Registrant.                      9
  
        4.2             Amended and Restated By-laws of the Registrant.                               *
                        Filed as Exhibit 3.3 to the Company's Annual Report
                        on Form 10-K for the fiscal year ended December 31,
                        1995.
  
        4.3             Rights Agreement dated as of March 1, 1996 between                            *
                        the Company and American Stock Transfer & Trust
                        Company.  Filed as Exhibit 1 to the Company's
                        Registration Statement on Form 8-A dated March 1,
                        1996.
  
        5.1             Opinion of Palmer & Dodge LLP as to the legality of                          19
                        the securities registered hereunder.
  
       23.1             Consent of Ernst & Young LLP, independent auditors.                          20
  
       23.2             Consent of Palmer & Dodge LLP (contained in                                  --
                        Opinion of Palmer & Dodge LLP, filed as Exhibit 5.1
                        hereto).
  
       24.1             Power of Attorney (set forth on the signature page to                        --
                        this Registration Statement).
  
       24.2             Certified resolution of the Board of Directors                               21
                        authorizing Power of Attorney.
  
       99.1             1995 Director Stock Option Plan.  Filed as Exhibit                            *
                        10.22 to the Company's Annual Report on Form 10-K
                        for the fiscal year ended December 31, 1995.
  
       99.2             Form of 1995 Director Stock Option Plan Nonstatutory                         22
                        Stock Option Certificate.
  - ----------------------------
  
  *  Incorporated herein by reference.
  
                                        - 8 -