As filed with the Securities and Exchange Commission on July 13, 1998
                                                     Registration No. 333-______
================================================================================



                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549


                                    FORM S-8
                             REGISTRATION STATEMENT
                                      Under
                           The Securities Act of 1933


                         MICROCIDE PHARMACEUTICALS, INC.
             (Exact name of Registrant as specified in its charter)


         Delaware                                        94-3186021
(State of incorporation)                    (I.R.S. Employer Identification No.)

                                850 Maude Avenue
                         Mountain View, California 94043
   (Address, including zip code, of Registrant's principal executive offices)


                        1993 AMENDED INCENTIVE STOCK PLAN
                            (Full title of the plan)


                                 JAMES E. RURKA
                       President, Chief Executive Officer
                                  and Director
                         MICROCIDE PHARMACEUTICALS, INC.
                                850 Maude Avenue
                         Mountain View, California 94043
                                 (650) 428-1550
(Name, address, and telephone number, including area code, of agent for service)


                                   Copies to:
                                VAHE H. SARRAFIAN
                        Wilson Sonsini Goodrich & Rosati
                            Professional Corporation
                               650 Page Mill Road
                               Palo Alto, CA 94306
                                 (650) 493-9300

<TABLE>
<CAPTION>
                                         CALCULATION OF REGISTRATION FEE
==========================================================================================================================
                                                               Proposed                Proposed                           
                                                               Maximum                  Maximum                           
          Title of Each Class            Amount               Offering                Aggregate              Amount of
            of Securities to             to be                  Price                  Offering             Registration
             be Registered            Registered(1)          Per Share(2)                Price                  Fee
--------------------------------------------------------------------------------------------------------------------------
<S>                                      <C>                  <C>                   <C>                       <C>    
Common Stock                             400,000              $6.47                 $2,598,000                $764.00
  $0.001 par value................   
==========================================================================================================================
</TABLE>

(1)  The shares covered by this Registration  Statement represent 400,000 shares
     of  Common  Stock  which  have  become  available  for  issuance  under the
     Registrant's  1993 Amended Incentive Stock Plan as a result of an amendment
     approved by the  stockholders  at the  Registrant's  Annual Meeting held on
     June 18,  1998  increasing  the number of shares  authorized  for  issuance
     thereunder from 1,880,000 to 2,280,000.

(2)  Estimated  in  accordance  with  Rule  457(c)  solely  for the  purpose  of
     calculating the registration fee based upon the average of the high and low
     prices of the Common Stock as reported on the Nasdaq National Market System
     on July 9, 1998.

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

<PAGE>



                      Statement Under General Instruction E
                      Registration of Additional Securities

     Unless  as  noted  herein,  the  contents  of  the  Registrant's  Form  S-8
Registration  Statements (File Nos. 333-11759 and 333-32785) are incorporated by
reference into this Registration Statement.

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT


Item 8.  Exhibits.

    Exhibit
    Number      Document
    ------      --------

        5.1     Opinion of Wilson Sonsini Goodrich & Rosati, a Professional
                Corporation.

       23.1     Consent of Ernst & Young LLP, Independent Auditors

       23.2     Consent of Counsel (contained in Exhibit 5.1).

       24.1     Power of Attorney (see page II-3).






<PAGE>



                                   SIGNATURES


     Pursuant to the requirements of the Securities Act of 1933, the Registrant,
Microcide  Pharmaceuticals,  Inc.,  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 Mountain View, State of
California, on this 10th day of July, 1998.


                                     MICROCIDE PHARMACEUTICALS, INC.



                                     By:   /s/James E. Rurka
                                           -------------------------------------
                                              James E. Rurka
                                              President, Chief Executive Officer



                                      II-2
<PAGE>


                                POWER OF ATTORNEY

     KNOW ALL PERSONS BY THESE  PRESENTS,  that each such person whose signature
appears below  constitutes and appoints,  jointly and severally,  James E. Rurka
and Matthew Hogan his  attorneys-in-fact,  each with the power of  substitution,
for him in any and all capacities,  to sign any amendments to this  Registration
Statement on Form S-8  (including  post-effective  amendments),  and to file the
same, with all 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, or his substitute or substitutes, 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  by  the  following  persons  in  the
capacities and on the dates indicated.



        Signature                          Title                      Date  
        ---------                          -----                      ----  

/s/James E. Rurka                President, Chief Executive      July 10, 1998
------------------------------   Officer, and Director
James E. Rurka                   (Principal Executive Officer)
                                   
/s/Matthew J. Hogan              Chief Financial Officer         July 10, 1998
------------------------------   (Principal Accounting and   
Matthew J. Hogan                 Financial Officer)          
                                 
                                 
/s/Keith A. Bostian, Ph.D.       Director                        July 10, 1998
------------------------------   
Keith A. Bostian, Ph.D.          

/s/Daniel L. Kisner, M.D.        Director                        July 10, 1998
------------------------------   
Daniel L. Kisner, M.D.           

/s/Hugh Y. Rienhoff, Jr., M.D.   Director                        July 10, 1998
------------------------------   
Hugh Y. Rienhoff, Jr., M.D.      

/s/David Schnell, M.D.           Director                        July 10, 1998
------------------------------   
David Schnell, M.D.              

/s/Mark B. Skaletsky             Director                        July 10, 1998
------------------------------
Mark B. Skaletsky                

/s/John P. Walker                Director                        July 10, 1998
------------------------------
John P. Walker                   

                                      II-3
<PAGE>


                                INDEX TO EXHIBITS



Exhibit
Number                            Exhibit
------                            -------

 5.1   Opinion of Wilson Sonsini Goodrich & Rosati, a Professional Corporation
23.1   Consent of Ernst & Young LLP, Independent Auditors
23.2   Consent of Counsel (included in Exhibit 5.1)
24.1   Power of Attorney (see page II-3)



                                      II-4
[{"type": "S-8", "sequence": "1", "description": "REGISTRATION STATEMENT", "secsgml_size_bytes": 8771}]
{"company-data": {"conformed-name": "MICROCIDE PHARMACEUTICALS INC", "cik": "0001010915", "assigned-sic": "2834", "irs-number": "943186021", "state-of-incorporation": "CA"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-58999", "film-number": "98665379"}, "business-address": {"street1": "850 MAUDE AVE", "city": "MOUNTAIN VIEW", "state": "CA", "zip": "94043", "phone": "4154281550"}, "mail-address": {"street1": "850 MAUDE AVE", "city": "MOUNTAIN VIEW", "state": "CA", "zip": "94043"}}
As filed with the Securities and Exchange Commission on July 13, 1998
                                                     Registration No. 333-______
================================================================================

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      Under
                           The Securities Act of 1933

                         MICROCIDE PHARMACEUTICALS, INC.
             (Exact name of Registrant as specified in its charter)

         Delaware                                        94-3186021
(State of incorporation)                    (I.R.S. Employer Identification No.)

                                850 Maude Avenue
                         Mountain View, California 94043
   (Address, including zip code, of Registrant's principal executive offices)

                        1993 AMENDED INCENTIVE STOCK PLAN
                            (Full title of the plan)

                                 JAMES E. RURKA
                       President, Chief Executive Officer
                                  and Director
                         MICROCIDE PHARMACEUTICALS, INC.
                                850 Maude Avenue
                         Mountain View, California 94043
                                 (650) 428-1550
(Name, address, and telephone number, including area code, of agent for service)

                                   Copies to:
                                VAHE H. SARRAFIAN
                        Wilson Sonsini Goodrich & Rosati
                            Professional Corporation
                               650 Page Mill Road
                               Palo Alto, CA 94306
                                 (650) 493-9300
CALCULATION OF REGISTRATION FEE
==========================================================================================================================
                                                               Proposed                Proposed                           
                                                               Maximum                  Maximum                           
          Title of Each Class            Amount               Offering                Aggregate              Amount of
            of Securities to             to be                  Price                  Offering             Registration
             be Registered            Registered(1)          Per Share(2)                Price                  Fee
--------------------------------------------------------------------------------------------------------------------------
Common Stock                             400,000              $6.47                 $2,598,000                $764.00
  $0.001 par value................   
==========================================================================================================================
(1)  The shares covered by this Registration  Statement represent 400,000 shares
     of  Common  Stock  which  have  become  available  for  issuance  under the
     Registrant's  1993 Amended Incentive Stock Plan as a result of an amendment
     approved by the  stockholders  at the  Registrant's  Annual Meeting held on
     June 18,  1998  increasing  the number of shares  authorized  for  issuance
     thereunder from 1,880,000 to 2,280,000.

(2)  Estimated  in  accordance  with  Rule  457(c)  solely  for the  purpose  of
     calculating the registration fee based upon the average of the high and low
     prices of the Common Stock as reported on the Nasdaq National Market System
     on July 9, 1998.

================================================================================
Statement Under General Instruction E
                      Registration of Additional Securities

     Unless  as  noted  herein,  the  contents  of  the  Registrant's  Form  S-8
Registration  Statements (File Nos. 333-11759 and 333-32785) are incorporated by
reference into this Registration Statement.

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 8.  Exhibits.

    Exhibit
    Number      Document
    ------      --------

        5.1     Opinion of Wilson Sonsini Goodrich & Rosati, a Professional
                Corporation.

       23.1     Consent of Ernst & Young LLP, Independent Auditors

       23.2     Consent of Counsel (contained in Exhibit 5.1).

       24.1     Power of Attorney (see page II-3).
SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the Registrant,
Microcide  Pharmaceuticals,  Inc.,  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 Mountain View, State of
California, on this 10th day of July, 1998.

                                     MICROCIDE PHARMACEUTICALS, INC.

                                     By:   /s/James E. Rurka
                                           -------------------------------------
                                              James E. Rurka
                                              President, Chief Executive Officer

                                      II-2
POWER OF ATTORNEY

     KNOW ALL PERSONS BY THESE  PRESENTS,  that each such person whose signature
appears below  constitutes and appoints,  jointly and severally,  James E. Rurka
and Matthew Hogan his  attorneys-in-fact,  each with the power of  substitution,
for him in any and all capacities,  to sign any amendments to this  Registration
Statement on Form S-8  (including  post-effective  amendments),  and to file the
same, with all 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, or his substitute or substitutes, 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  by  the  following  persons  in  the
capacities and on the dates indicated.

        Signature                          Title                      Date  
        ---------                          -----                      ----  

/s/James E. Rurka                President, Chief Executive      July 10, 1998
------------------------------   Officer, and Director
James E. Rurka                   (Principal Executive Officer)
                                   
/s/Matthew J. Hogan              Chief Financial Officer         July 10, 1998
------------------------------   (Principal Accounting and   
Matthew J. Hogan                 Financial Officer)          
                                 
                                 
/s/Keith A. Bostian, Ph.D.       Director                        July 10, 1998
------------------------------   
Keith A. Bostian, Ph.D.          

/s/Daniel L. Kisner, M.D.        Director                        July 10, 1998
------------------------------   
Daniel L. Kisner, M.D.           

/s/Hugh Y. Rienhoff, Jr., M.D.   Director                        July 10, 1998
------------------------------   
Hugh Y. Rienhoff, Jr., M.D.      

/s/David Schnell, M.D.           Director                        July 10, 1998
------------------------------   
David Schnell, M.D.              

/s/Mark B. Skaletsky             Director                        July 10, 1998
------------------------------
Mark B. Skaletsky                

/s/John P. Walker                Director                        July 10, 1998
------------------------------
John P. Walker                   

                                      II-3
INDEX TO EXHIBITS

Exhibit
Number                            Exhibit
------                            -------

 5.1   Opinion of Wilson Sonsini Goodrich & Rosati, a Professional Corporation
23.1   Consent of Ernst & Young LLP, Independent Auditors
23.2   Consent of Counsel (included in Exhibit 5.1)
24.1   Power of Attorney (see page II-3)

                                      II-4