As filed with the Securities and Exchange Commission on January 31, 1996
                   Registration No. 33-64665                        
                                                                    
                                                                    
                                         

                  SECURITIES AND EXCHANGE COMMISSION
                        Washington, DC  20549
                                             

                    POST-EFFECTIVE AMENDMENT NO. 1
                                  TO
                               FORM S-8
                        REGISTRATION STATEMENT
                                Under
                      THE SECURITIES ACT OF 1933

                                             

                          MERCK & CO., INC.
             (Exact name of registrant as specified in its charter)

          New Jersey                              22-1109110
  (State or other jurisdiction of            (I.R.S. Employer
  incorporation or organization)             Identification No.)
                   

        One Merck Drive
        Whitehouse Station, NJ                           08889-0100
  (Address of principal executive offices                (Zip Code)


                           ASTRA MERCK INC.
                  EMPLOYEE SAVINGS AND SECURITY PLAN
                         (Full title of the plan)


                           CELIA A. COLBERT
               Secretary and Assistant General Counsel
                          Merck & Co., Inc.
                           One Merck Drive
              Whitehouse Station, New Jersey  08889-0100
                   (Name and address of agent for service)

                            (908) 423-1000
         (Telephone number, including area code, of agent for service)
                                              


                    Copy of all communications to:

                     ROBERT J. LICHTENSTEIN, ESQ.
                     Morgan, Lewis & Bockius LLP
                        2000 One Logan Square
                       Philadelphia, PA  19103
                            (215) 963-5726



  Item 8.  Exhibits.

       The exhibits  filed as  part of this  Registration Statement
  are as follows:

  Exhibit                                           Method of
  Number                   Exhibit                     Filing  

    5.1     Opinion re legality (Common Stock of 
            Registrant) (1)                        Previously filed

    5.2     Opinion of Morgan, Lewis & Bockius LLP 
            (interests in Plan)                    Previously filed

   23.1     Consent of Arthur Andersen LLP         Previously filed

   23.2     Consent of Price Waterhouse LLP        Previously filed

   23.3     Consent of Morgan, Lewis & Bockius LLP
            (included in Exhibit 5.2)              Previously filed

   24       Power of Attorney and Certified Resolution 
            of Board of Directors                  Previously filed

   99       Astra Merck Inc. Employee Savings and 
            Security Plan                           Filed herewith



  (1)          In  lieu   of  an  opinion   of  counsel   concerning
               compliance with  the  requirements  of  the  Employee
               Retirement  Income Security  Act of  1974 as  amended
               ("ERISA")  and  an  Internal Revenue  Service ("IRS")
               determination  letter  that  the  Plan  is  qualified
               under Section  401 of  the Internal  Revenue Code  of
               1986, as  amended, the  Registrant hereby  undertakes
               to  submit the Plan  to the  IRS in  a timely manner,
               and shall  make all changes required  by the IRS,  in
               order to qualify the Plan.








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                             SIGNATURES 

                      The Registrant.  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
  Amendment to be signed on its behalf by the undersigned,
  thereunto duly authorized, in Whitehouse Station, New Jersey, on
  the 19th day of December, 1995.

                                     MERCK & CO., INC.


                              By:                 *        
                                    RAYMOND V. GILMARTIN
                                   Chairman of the Board, President
                                   and Chief
                                    Executive Office and Director


                              By:  /s/ Celia A. Colbert             
                                    CELIA A. COLBERT
                                    Secretary and Assistant
                                    General Counsel
                                                                 
  (Attorney-in-fact)


                      Pursuant to the requirements of the
  Securities Act 1933, this Registration Statement has been signed
  below by the following persons in the capacities and on the date
  indicated.


  Signatures             Title                              Date


      *                  Chairman of the Board,        December 19, 1995
  Raymond V. Gilmartin   President and Chief Executive Officer;
                         Principal Executive Officer; Director

      *                  Senior Vice President         December 19, 1995
  Judy C. Lewent         and Chief Accounting Officer;
                         Principal Financial Officer


       *                 Vice President, Controller;   December 19, 1995
  Peter E. Nugent        Principal Accounting Officer


       *                 Director                      December 19, 1995
  H. Brewster Atwater, Jr.


       *                 Director                      December 19, 1995
  Derek Birkin


        *                Director                      December 19, 1995
  Lawrence A. Bossidy


                              2  


        *                Director                      December 19, 1995
  William G. Bowen, Ph.D.


        *                Director                      December 19, 1995
  Johnnetta B. Cole, Ph.D.


        *                Director                      December 19, 1995
  Carolyne K. Davis, Ph.D.


        *                Director                      December 19, 1995
  Lloyd C. Elam, M.D.


        *                Director                      December 19, 1995
  Charles E. Exley, Jr.


         *               Director                      December 19, 1995
  William N. Kelley, M.D.


         *               Director                      December 19, 1995
  Samuel O. Thier, M.D.


         *               Director                      December 19, 1995
  Dennis Weatherstone

                         Celia A. Colbert, by signing her name
  hereto, does hereby sign this document pursuant to powers of
  attorney duly executed by the persons named, filed with the
  Securities and Exchange Commission as an exhibit to the
  Registration Statement, on behalf of such persons, all in the
  capacities and on the date stated, such persons including a
  majority of the directors of the Company.

                              By:  /s/ Celia A. Colbert             
                                    CELIA A. COLBERT
                                    Secretary and Assistant
                                    General Counsel
                                    (Attorney-in-Fact)

                         The Plan.  Pursuant to the requirements of
  the Securities Act of 1933, the Plan has duly caused this
  Amendment to be signed on its behalf by the undersigned,
  thereunto duly authorized, in Wayne, Pennsylvania on December 18,
  1995.

                              ASTRA MERCK INC.
                              EMPLOYEE SAVINGS AND SECURITY PLAN

                              By: /s/ Linda E. Robertson            
                              Name:  Linda E. Robertson
                              Title:   Administrative Committee





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                          INDEX TO EXHIBITS



                                                      Sequentially
  Exhibit                                               Numbered
  Number                   Exhibit                        Page


     5.1    Opinion re legality (Common Stock 
            of Registrant) (1)                     Previously Filed

     5.2    Opinion of Morgan, Lewis & Bockius LLP 
            (interests in Plan)                    Previously Filed

    23.1    Consent of Arthur Andersen LLP         Previously Filed

    23.2    Consent of Price Waterhouse LLP        Previously Filed

    23.3    Consent of Morgan, Lewis & Bockius LLP 
            (included in Exhibit 5.2)              Previously Filed

    24      Power of Attorney and Certified Resolution 
            of Board of Directors                  Previously Filed

    99      Astra Merck Inc. Employee Savings 
            and Security Plan                   

  (1)          In  lieu   of  an  opinion   of  counsel   concerning
               compliance  with  the  requirements  of the  Employee
               Retirement  Income Security  Act of  1974 as  amended
               ("ERISA")  and an  Internal Revenue  Service  ("IRS")
               determination  letter  that  the  Plan  is  qualified
               under Section  401 of  the Internal  Revenue Code  of
               1986, as  amended, the  Registrant hereby  undertakes
               to  submit the Plan  to the  IRS in  a timely manner,
               and  shall make all  changes required  by the IRS, in
               order to qualify the Plan.















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