<PAGE>
 
   As filed with the Securities and Exchange Commission on February 13, 1996
                    Registration No. 33-__________________

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

                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C.  20549

                                   FORM S-8
                         REGISTRATION STATEMENT UNDER
                          THE SECURITIES ACT OF 1933
                                        
                              MYCOGEN CORPORATION
       -----------------------------------------------------------------
            (Exact name of registrant as specified in its charter)

           California                                     95-3802654
--------------------------------                   ----------------------
(State or other jurisdiction of                       (I.R.S. Employer
 incorporation or organization)                      Identification No.)


5501 Oberlin Drive,  San Diego, California                  92121
------------------------------------------               -----------
 (Address of principal executive offices)                 (Zip Code)

                                        
                       1995 EMPLOYEE STOCK PURCHASE PLAN
                    --------------------------------------
                           (Full title of the plan)


                                CARLTON J. EIBL
               President, Chief Operating Officer and Secretary
               5501 Oberlin Drive,  San Diego, California  92121
             ----------------------------------------------------
                    (Name and address of agent for service)
                     
                   
                                 619-453-8030
                                 ------------
         (Telephone number, including area code, of agent for service)

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

         This Registration Statement shall become effective immediately
            upon filing with the Securities and Exchange Commission,
          and sales of the registered securities will begin as soon as
               reasonably practicable after such effective date.

                     ------------------------------------
<PAGE>
 
                        CALCULATION OF REGISTRATION FEE
<TABLE> 
<CAPTION>
Title of securities     Amount to be         Proposed maximum            Proposed maximum           Amount of
to be registered         registered      offering price per share    aggregate offering price    registration fee
-----------------------------------------------------------------------------------------------------------------
<S>                     <C>              <C>                         <C>                         <C> 
Common Stock,            250,000 (1)            $16.00 (2)                $4,000,000 (2)             $1,379.31
$.001 par value
</TABLE> 
------------
(1)  This Registration Statement shall also cover any additional shares of
Common Stock which become issuable under the 1995 Employee Stock Purchase Plan
by reason of any stock dividend, stock split, recapitalization or other similar
transaction effected without the receipt of consideration which results in an
increase in the number of the Registrant's outstanding shares of Common Stock.

(2)  Calculated solely for purposes of this offering under rule 457 (h) of the
Securities Act of 1933, as amended, on the basis of the last sale reported per
share of Common Stock of Mycogen Corporation on February 7, 1996, as reported on
the NASDAQ National Market System.

                                       2
<PAGE>
 
Item 3.  Incorporation Of Certain Documents By Reference.
         ------------------------------------------------

     Mycogen Corporation (the "Registrant") hereby incorporates by reference
into this Registration Statement the following documents previously filed with
the Securities and Exchange Commission (the "Commission"):

     (a)  the Registrant's Annual Report on Form 10-K for the fiscal year ended
August 31, 1995, filed by the Registrant on November 3, 1995;

     (b)   (1)  The Registrant's Quarterly Report on Form 10-Q for the quarterly
period ended November 30, 1995, filed by the Registrant on January 16, 1996;

           (2) The Registrant's report on Form 8-K, filed with the Commission on
November 27, 1995;

     (c)  The Registrant's Registration Statement No. 0-15881 on Form 8-A filed
with the Commission on May 7, 1992, in which there is described the terms,
rights and provisions applicable to the Registrant's Common Stock.

     All reports and definitive proxy or information statements filed pursuant
to Section 13(a), 13(c), 14 or 15(d) of the 1934 Act after the date of this
Registration Statement and prior to the filing of a post-effective amendment
which indicates that all securities offered hereby have been sold or which
deregisters all securities then remaining unsold shall be deemed to be
incorporated by reference into this Registration Statement and to be a part
hereof from the date of filling of such documents.


Item 4.  Description of Securities.
         --------------------------

     Not applicable.


Item 5.  Interests of Named Experts and Counsel.
         ---------------------------------------

     Registrant's President has delivered to Registrant a legal opinion as to
the validity of the issuance of Common Stock under this Registration Statement.


Item 6.  Indemnification of Directors and Officers.
         ------------------------------------------

     The California General Corporation Law provides that directors will not be
liable to the Registrant for monetary damages arising from a breach of their
fiduciary duty as directors in certain circumstances, including such conduct
during a merger or tender offer.  Such limitation does not affect liability for
any breach of a director's duty to the Registrant or its shareholders (i) with
respect to approval by the director of any transaction from which he or she
derives an

                                       3
<PAGE>
 
improper personal benefit; (ii) with respect to any acts or omissions involving
an absence of good faith, which he or she believes to be contrary to the best
interests of the Company or its shareholders, which involve intentional
misconduct or a knowing and culpable violation of law, which constitute an
unexcused pattern of inattention that amounts to an abdication of his or her
duty to the Registrant or its shareholders, or which show a reckless disregard
for his or her duty to the Registrant or its shareholders in circumstances in
which he or she was, or should have been, aware, in the ordinary course of
performing his or her duties, of a risk of serious injury to the Registrant or
its shareholders; or (iii) based on transactions between the Registrant and its
directors or another corporation with interrelated directors, or on improper
distributions, loans or guarantees under applicable sections of the California
Corporations Code. In addition, such limitation of liability does not affect the
availability of equitable remedies such as injunctive relief or rescission,
although in certain circumstances equitable relief may not be available as a
practical matter. Such limitation may relieve the directors of monetary
liability to the Registrant for grossly negligent conduct, including conduct in
situations involving attempted takeovers of the Registrant. No claim or
litigation is currently pending against the Registrant's directors that would be
affected by such limitation of liability.

     Article X of the Articles of Incorporation of the Registrant and Article V
of the Registrant's Bylaws provide for indemnification of its directors,
officers and other agents to the maximum extent permitted by the California
Corporations Code.  The Registrant maintains insurance for the benefit of its
current directors and officers that insures such persons against certain
liabilities, including liabilities under the securities laws.  The Registrant
has entered into an indemnification agreement with each of its current directors
and executive officers whereby the Registrant will reimburse its current
directors and such officers against certain liabilities, including liabilities
arising under the securities laws.

Item 7.  Exception from Registration Claimed.
         ------------------------------------

     Not applicable.

Item 8.  Exhibits.
         ---------

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

  5            Opinion and Consent of Carlton J. Eibl, Esq.

 10.1          1995 Employee Stock Purchase Plan

 10.2          Employee Stock Purchase Plan Summary and Prospectus

 23            Consent of Ernst & Young LLP, Independent Auditors

 24            Power of Attorney

                                       4
<PAGE>
 
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, represent a fundamental change in the information set forth in
this Registration Statement; and (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 clauses (1)(i) and (1)(ii) shall
                        --------
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 into this Registration Statement;
(2) that for the purpose of determining any liability under the Securities Act
of 1933 each such post-effective amendment will 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; and (3) to remove from registration by means of a post-
effective amendment any of the securities being registered which remain unsold
upon the termination of the 1995 Employee Stock Purchase Plan.

     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 into this
Registration Statement will 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 or controlling
persons of the Registrant pursuant to the indemnity provisions incorporated by
reference in Item 6, or otherwise, the Registrant has been informed that in the
opinion of the Commission such indemnification is against public policy as
expressed in the 1933 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 1933 Act
and will be governed by the final adjudication of such issue.

                                       5
<PAGE>
 
                                   SIGNATURES
                                   ----------
                                        
     Pursuant to the requirements of the 1933 Act, 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 San
Diego, State of California, on this 9th day of February, 1996.

                                    MYCOGEN CORPORATION

Date:  February 9, 1996             By  /s/ Jerry Caulder
       --------------------             ------------------------------- 
                                        Jerry Caulder, Chairman and
                                        Chief Executive Officer

     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 date indicated.
<TABLE>

<S>                        <C>                                  <C>
    /s/ Jerry Caulder      Chairman, Chief Executive
-------------------------  Officer and Director (Principal      February 9, 1996
     (Jerry Caulder)       Executive Officer)


  /s/ James A. Baumker
-------------------------  Director                             February 9, 1996
   (Thomas J. Cable*)


  /s/ James A. Baumker
-------------------------  Director                             February 9, 1996
   (George R. Hill*)


  /s/ James A. Baumker
-------------------------  Director                             February 9, 1996
  (Kenneth H. Hopping)


  /s/ James A. Baumker
-------------------------  Director                             February 9, 1996
   (David H. Rammler*)


  /s/ James A. Baumker
-------------------------  Director                             February 9, 1996
  (A. John Speziale*)


  /s/ James A. Baumker     Vice President and Chief
-------------------------  Financial Officer (Principal         February 9, 1996
   (James A. Baumker)      Financial and Accounting Officer)
</TABLE>

*  By James A. Baumker under power of attorney.

                                       6
<PAGE>
 
                                 EXHIBIT INDEX

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

  5            Opinion and Consent of Carlton J. Eibl, Esq.

 10.1          1995 Employee Stock Purchase Plan

 10.2          Employee Stock Purchase Plan Summary and Prospectus

 23            Consent of Ernst & Young LLP, Independent Auditors

 24            Power of Attorney

                                       7
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 15107}]
{"company-data": {"conformed-name": "MYCOGEN CORP", "cik": "0000813742", "assigned-sic": "0700", "irs-number": "953802654", "state-of-incorporation": "DE", "fiscal-year-end": "0831"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-00899", "film-number": "96517680"}, "business-address": {"street1": "5501 OBERLIN DRIVE", "city": "SAN DIEGO", "state": "CA", "zip": "92121", "phone": "6194538030"}, "mail-address": {"street1": "5501 OBERLIN DRIVE", "city": "SAN DIEGO", "state": "CA", "zip": "92121"}}
As filed with the Securities and Exchange Commission on February 13, 1996
                    Registration No. 33-__________________

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

                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C.  20549

                                   FORM S-8
                         REGISTRATION STATEMENT UNDER
                          THE SECURITIES ACT OF 1933
                                        
                              MYCOGEN CORPORATION
       -----------------------------------------------------------------
            (Exact name of registrant as specified in its charter)

           California                                     95-3802654
--------------------------------                   ----------------------
(State or other jurisdiction of                       (I.R.S. Employer
 incorporation or organization)                      Identification No.)

5501 Oberlin Drive,  San Diego, California                  92121
------------------------------------------               -----------
 (Address of principal executive offices)                 (Zip Code)

                                        
                       1995 EMPLOYEE STOCK PURCHASE PLAN
                    --------------------------------------
                           (Full title of the plan)

                                CARLTON J. EIBL
               President, Chief Operating Officer and Secretary
               5501 Oberlin Drive,  San Diego, California  92121
             ----------------------------------------------------
                    (Name and address of agent for service)
                     
                   
                                 619-453-8030
                                 ------------
         (Telephone number, including area code, of agent for service)

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

         This Registration Statement shall become effective immediately
            upon filing with the Securities and Exchange Commission,
          and sales of the registered securities will begin as soon as
               reasonably practicable after such effective date.

                     ------------------------------------
CALCULATION OF REGISTRATION FEE
Title of securities     Amount to be         Proposed maximum            Proposed maximum           Amount of
to be registered         registered      offering price per share    aggregate offering price    registration fee
-----------------------------------------------------------------------------------------------------------------
Common Stock,            250,000 (1)            $16.00 (2)                $4,000,000 (2)             $1,379.31
$.001 par value
------------
(1)  This Registration Statement shall also cover any additional shares of
Common Stock which become issuable under the 1995 Employee Stock Purchase Plan
by reason of any stock dividend, stock split, recapitalization or other similar
transaction effected without the receipt of consideration which results in an
increase in the number of the Registrant's outstanding shares of Common Stock.

(2)  Calculated solely for purposes of this offering under rule 457 (h) of the
Securities Act of 1933, as amended, on the basis of the last sale reported per
share of Common Stock of Mycogen Corporation on February 7, 1996, as reported on
the NASDAQ National Market System.

                                       2
Item 3.  Incorporation Of Certain Documents By Reference.
         ------------------------------------------------

     Mycogen Corporation (the "Registrant") hereby incorporates by reference
into this Registration Statement the following documents previously filed with
the Securities and Exchange Commission (the "Commission"):

     (a)  the Registrant's Annual Report on Form 10-K for the fiscal year ended
August 31, 1995, filed by the Registrant on November 3, 1995;

     (b)   (1)  The Registrant's Quarterly Report on Form 10-Q for the quarterly
period ended November 30, 1995, filed by the Registrant on January 16, 1996;

           (2) The Registrant's report on Form 8-K, filed with the Commission on
November 27, 1995;

     (c)  The Registrant's Registration Statement No. 0-15881 on Form 8-A filed
with the Commission on May 7, 1992, in which there is described the terms,
rights and provisions applicable to the Registrant's Common Stock.

     All reports and definitive proxy or information statements filed pursuant
to Section 13(a), 13(c), 14 or 15(d) of the 1934 Act after the date of this
Registration Statement and prior to the filing of a post-effective amendment
which indicates that all securities offered hereby have been sold or which
deregisters all securities then remaining unsold shall be deemed to be
incorporated by reference into this Registration Statement and to be a part
hereof from the date of filling of such documents.

Item 4.  Description of Securities.
         --------------------------

     Not applicable.

Item 5.  Interests of Named Experts and Counsel.
         ---------------------------------------

     Registrant's President has delivered to Registrant a legal opinion as to
the validity of the issuance of Common Stock under this Registration Statement.

Item 6.  Indemnification of Directors and Officers.
         ------------------------------------------

     The California General Corporation Law provides that directors will not be
liable to the Registrant for monetary damages arising from a breach of their
fiduciary duty as directors in certain circumstances, including such conduct
during a merger or tender offer.  Such limitation does not affect liability for
any breach of a director's duty to the Registrant or its shareholders (i) with
respect to approval by the director of any transaction from which he or she
derives an

                                       3
improper personal benefit; (ii) with respect to any acts or omissions involving
an absence of good faith, which he or she believes to be contrary to the best
interests of the Company or its shareholders, which involve intentional
misconduct or a knowing and culpable violation of law, which constitute an
unexcused pattern of inattention that amounts to an abdication of his or her
duty to the Registrant or its shareholders, or which show a reckless disregard
for his or her duty to the Registrant or its shareholders in circumstances in
which he or she was, or should have been, aware, in the ordinary course of
performing his or her duties, of a risk of serious injury to the Registrant or
its shareholders; or (iii) based on transactions between the Registrant and its
directors or another corporation with interrelated directors, or on improper
distributions, loans or guarantees under applicable sections of the California
Corporations Code. In addition, such limitation of liability does not affect the
availability of equitable remedies such as injunctive relief or rescission,
although in certain circumstances equitable relief may not be available as a
practical matter. Such limitation may relieve the directors of monetary
liability to the Registrant for grossly negligent conduct, including conduct in
situations involving attempted takeovers of the Registrant. No claim or
litigation is currently pending against the Registrant's directors that would be
affected by such limitation of liability.

     Article X of the Articles of Incorporation of the Registrant and Article V
of the Registrant's Bylaws provide for indemnification of its directors,
officers and other agents to the maximum extent permitted by the California
Corporations Code.  The Registrant maintains insurance for the benefit of its
current directors and officers that insures such persons against certain
liabilities, including liabilities under the securities laws.  The Registrant
has entered into an indemnification agreement with each of its current directors
and executive officers whereby the Registrant will reimburse its current
directors and such officers against certain liabilities, including liabilities
arising under the securities laws.

Item 7.  Exception from Registration Claimed.
         ------------------------------------

     Not applicable.

Item 8.  Exhibits.
         ---------

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

  5            Opinion and Consent of Carlton J. Eibl, Esq.

 10.1          1995 Employee Stock Purchase Plan

 10.2          Employee Stock Purchase Plan Summary and Prospectus

 23            Consent of Ernst & Young LLP, Independent Auditors

 24            Power of Attorney

                                       4
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, represent a fundamental change in the information set forth in
this Registration Statement; and (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 clauses (1)(i) and (1)(ii) shall
                        --------
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 into this Registration Statement;
(2) that for the purpose of determining any liability under the Securities Act
of 1933 each such post-effective amendment will 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; and (3) to remove from registration by means of a post-
effective amendment any of the securities being registered which remain unsold
upon the termination of the 1995 Employee Stock Purchase Plan.

     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 into this
Registration Statement will 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 or controlling
persons of the Registrant pursuant to the indemnity provisions incorporated by
reference in Item 6, or otherwise, the Registrant has been informed that in the
opinion of the Commission such indemnification is against public policy as
expressed in the 1933 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 1933 Act
and will be governed by the final adjudication of such issue.

                                       5
SIGNATURES
                                   ----------
                                        
     Pursuant to the requirements of the 1933 Act, 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 San
Diego, State of California, on this 9th day of February, 1996.

                                    MYCOGEN CORPORATION

Date:  February 9, 1996             By  /s/ Jerry Caulder
       --------------------             ------------------------------- 
                                        Jerry Caulder, Chairman and
                                        Chief Executive Officer

     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 date indicated.
/s/ Jerry Caulder      Chairman, Chief Executive
-------------------------  Officer and Director (Principal      February 9, 1996
     (Jerry Caulder)       Executive Officer)

  /s/ James A. Baumker
-------------------------  Director                             February 9, 1996
   (Thomas J. Cable*)

  /s/ James A. Baumker
-------------------------  Director                             February 9, 1996
   (George R. Hill*)

  /s/ James A. Baumker
-------------------------  Director                             February 9, 1996
  (Kenneth H. Hopping)

  /s/ James A. Baumker
-------------------------  Director                             February 9, 1996
   (David H. Rammler*)

  /s/ James A. Baumker
-------------------------  Director                             February 9, 1996
  (A. John Speziale*)

  /s/ James A. Baumker     Vice President and Chief
-------------------------  Financial Officer (Principal         February 9, 1996
   (James A. Baumker)      Financial and Accounting Officer)
*  By James A. Baumker under power of attorney.

                                       6
EXHIBIT INDEX

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

  5            Opinion and Consent of Carlton J. Eibl, Esq.

 10.1          1995 Employee Stock Purchase Plan

 10.2          Employee Stock Purchase Plan Summary and Prospectus

 23            Consent of Ernst & Young LLP, Independent Auditors

 24            Power of Attorney

                                       7