<PAGE>

      As filed with the Securities and Exchange Commission on February 13, 1997
                                                     Registration No. 333-
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


                          SECURITIES AND EXCHANGE COMMISSION
                                Washington, D.C. 20549

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

                                       FORM S-8
                                REGISTRATION STATEMENT
                                        UNDER
                              THE SECURITIES ACT OF 1933

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


                                    COCENSYS, INC.
                (Exact name of registrant as specified in its charter)

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

       DELAWARE                                         33-0538836
(State of Incorporation)                   (I.R.S. Employer Identification No.)

                                 213 TECHNOLOGY DRIVE
                               IRVINE, CALIFORNIA 92718
            (Address and telephone number of principal executive offices)

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


                                  ISSUANCE AGREEMENT
                              (Full title of the plans)

                               F. Richard Nichol, Ph.D.
                        President and Chief Executive Officer
                                    CoCensys, Inc.
                                 213 Technology Drive
                               Irvine, California 92718
              (Name, address, including zip code, and telephone number,
                      including area code, of agent for service)

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

                                      Copies to:
                               Alan C. Mendelson, Esq.
                                  Cooley Godward LLP
                                Five Palo Alto Square
                             Palo Alto, California 94306

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

                           CALCULATION OF REGISTRATION FEE

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
<TABLE>
<CAPTION>

------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------
                                             PROPOSED MAXIMUM         PROPOSED MAXIMUM
TITLE OF SECURITIES     AMOUNT TO BE        OFFERING PRICE PER       AGGREGATE OFFERING      AMOUNT OF
 TO BE REGISTERED        REGISTERED             SHARE (1)                PRICE (1)        REGISTRATION FEE
------------------------------------------------------------------------------------------------------------
<S>                      <C>                    <C>                   <C>                    <C>
Common Stock (par         21,094                  $6.5625                $138,429.38           $42.00
value $.001)
------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------

</TABLE>

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

(1) Estimated solely for the purpose of calculating the amount of the
    registration fee pursuant to Rule 457(h).  The price per share and
    aggregate offering price are based upon the average of the high and low
    prices of Registrant's Common Stock on February 10, 1997 as reported on the
    Nasdaq National Market.

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


    Approximate date of commencement of proposed sale to the public:  As soon
as practicable after this Registration Statement becomes effective.

<PAGE>

ITEM 3.  INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

    The following documents filed by CoCensys, Inc., a Delaware corporation
(the "Company") with the Securities and Exchange Commission are incorporated by
reference into this Registration Statement:

         (a)  The Company's annual report on Form 10-K, as amended by form
10-K/A for the year ended December 31, 1995.

    (b)  The Company's quarterly reports on Form 10-Q for the quarters ended
March 31, June 30 and September 30, 1996.

    (c)  The Company's current report on Form 8-K, filed January 5, 1996.

    (d)  The description of the Company's Common Stock contained in the
Company's registration statement on Form 8-A filed December 10, 1992.

    (e)  The description of the Company's Preferred Share Purchase Rights
contained in the Company's registration statement on form 8-A filed May 16,
1995.

    All reports and other documents subsequently filed by the Company pursuant
to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act prior to the filing
of a post-effective amendment which indicates that all securities offered have
been sold or which deregisters all securities then remaining unsold, shall be
deemed to be incorporated by reference herein and to be a part of this
registration statement 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

    Not Applicable.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS

    Under Section 145 of the Delaware General Corporation Law, the Company has
broad powers to indemnify its directors and officers against liabilities they
may incur in such capacities, including liabilities under the Securities Act.
The Company's Bylaws require the Company to indemnify its directors and
executive officers, and permit the Company to indemnify its other officers,
employees and other agents, to the fullest extent permitted by Delaware law;
provided, however, that the Company may limit the extent of such indemnification
by individual contracts with its directors and executive officers; and provided
further, that the Company shall not be required to indemnify any director or
executive officer in connection with any proceeding (or part thereof) initiated
by such person or any proceeding by such person against the Company or its
directors, officers, employees or other agents unless (i) such indemnification
is expressly required to be made by law, (ii) the proceeding was authorized by
the Board of Directors of the Company, or (iii) such indemnification is provided
by the Company, in its sole discretion, pursuant to the powers vested in the
Company under the Delaware General Corporation Law.  The Bylaws also require the
Company to advance, prior to the final disposition of any proceeding, promptly
following request therefor, all expenses incurred by any director or executive
officer in connection with such proceeding, upon receipt of an undertaking by or
on behalf of such person to repay said amounts if it should be determined
ultimately that such person is not entitled to be indemnified under the
Company's Bylaws or otherwise.

    The Company has entered into indemnity agreements with each of its
directors and executive officers.  Such indemnity agreements contain provisions
which are in some respects broader than the specific indemnification provisions
contained in Delaware law.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED

    Not Applicable.


                                          2.

<PAGE>

ITEM 8.  EXHIBITS

EXHIBIT
NUMBER

5        Opinion of Cooley Godward LLP

23.1     Consent of Ernst & Young LLP

23.2     Consent of Cooley Godward LLP is contained in Exhibit 5 to this
         Registration Statement.

99.1     Issuance Agreement


ITEM 9.  UNDERTAKINGS

    1.   The undersigned registrant hereby undertakes:

         (a)  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;

          (ii)     To reflect in the prospectus any facts or events arising
after the effective date of the 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 the registration
statement.

         (iii)     To include any material information with respect to the plan
of distribution not previously disclosed in the registration statement or any
material change to such information in the registration statement;

    PROVIDED, HOWEVER, that paragraphs (a)(i) and (a)(ii) do not apply if the
registration statement is on Form S-3 or Form S-8 and the information required
to be included in a post-effective amendment by those paragraphs is contained in
periodic reports filed by the issuer pursuant to section 13 or section 15(d) of
the Exchange Act that are incorporated by reference in the registration
statement.

         (b)  That, for the purpose of determining any liability under the
Securities Act, each such post-effective amendment shall be deemed to be a new
registration statement relating to the securities offered herein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

         (c)  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.

    2.   The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act, each filing of the
registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Exchange Act that is incorporated by reference in the Registration Statement
shall be deemed to be a new registration statement relating to the securities
offered herein, and the offering of such securities at that time shall be deemed
to be the initial bona fide offering thereof.


                                          3.

<PAGE>

    3.   Insofar as indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers and controlling persons
of the registrant pursuant to the foregoing provisions, 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
Securities 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 Securities
Act and will be governed by the final adjudication of such issue.


                                          4.

<PAGE>

                                      SIGNATURES

    THE REGISTRANT.  Pursuant to the requirements of the Securities Act of
1933, as amended, 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 Irvine, State of
California, on February 12, 1997.


                                       COCENSYS, INC.

                                         /s/ F. Richard Nichol
                                       ----------------------------------------
                                       F. Richard Nichol
                                       President and
                                       Chief Executive Officer



                                  POWER OF ATTORNEY


    KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints F. RICHARD NICHOL and PETER E. JANSEN and
each or any one of them, his true and lawful attorney-in-fact and agent, with
full power of substitution and resubstitution, for him and in his name, place
and stead, in any and all capacities, to sign any and all amendments (including
post-effective amendments) to this Registration Statement, and to file the same,
with all exhibits thereto, and other documents in connection therewith, with the
Securities and Exchange Commission, granting unto said attorneys-in-fact and
agents, and each of them, full power and authority to do and perform each and
every act and thing requisite and necessary to be done in connection therewith,
as fully to all intents and purposes as he might or could do in person, hereby
ratifying and confirming all that said attorneys-in-fact and agents, or any of
them, or their or his substitutes or substitute, may lawfully do or cause to be
done by virtue hereof.


<PAGE>

    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/ Lowell E. Sears          Chairman of the Board            February 12, 1997
-------------------------
Lowell E. Sears


/s/ F. Richard Nichol        President and Chief              February 12, 1997
-------------------------    Executive Officer;
F. Richard Nichol, Ph.D.     Director


/s/ Peter E. Jansen          Vice President and Chief         February 12, 1997
-------------------------    Financial Officer
Peter E. Jansen              (Principal Financial Officer)


/s/ Alan C. Mendelson        Director                         February 12, 1997
-------------------------
Alan C. Mendelson


/s/ James C. Blair           Director                         February 12, 1997
-------------------------
James C. Blair, Ph.D.


/s/ Kelvin W. Gee            Director                         February 12, 1997
-------------------------
Kelvin W. Gee, Ph.D.


/s/ Robert G. McNeil         Director                         February 12, 1997
-------------------------
Robert G. McNeil, Ph.D.


/s/ Timothy J. Rink          Director                         February 12, 1997
-------------------------
Timothy J. Rink, M.D., Sc.D.


/s/ Eckard Weber             Director                         February 12, 1997
-------------------------
Eckard Weber, M.D.



<PAGE>


                                    EXHIBIT INDEX
EXHIBIT
NUMBER                  DESCRIPTION                   

 5       Opinion of Cooley Godward LLP

23.1     Consent of Ernst & Young LLP

23.2     Consent of Cooley Godward LLP is contained
         in Exhibit 5 to this Registration Statement

99.1     Issuance Agreement
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 15502}]
{"company-data": {"conformed-name": "COCENSYS INC", "cik": "0000895034", "assigned-sic": "2834", "irs-number": "330538836", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-21761", "film-number": "97531523"}, "business-address": {"street1": "213 TECHNOLOGY DR", "city": "IRVINE", "state": "CA", "zip": "92718", "phone": "7147536100"}, "mail-address": {"street2": "213 TECHNOLOGY DRIVE", "city": "IRVINE", "state": "CA", "zip": "92718"}}
As filed with the Securities and Exchange Commission on February 13, 1997
                                                     Registration No. 333-
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------

                          SECURITIES AND EXCHANGE COMMISSION
                                Washington, D.C. 20549

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

                                       FORM S-8
                                REGISTRATION STATEMENT
                                        UNDER
                              THE SECURITIES ACT OF 1933

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

                                    COCENSYS, INC.
                (Exact name of registrant as specified in its charter)

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

       DELAWARE                                         33-0538836
(State of Incorporation)                   (I.R.S. Employer Identification No.)

                                 213 TECHNOLOGY DRIVE
                               IRVINE, CALIFORNIA 92718
            (Address and telephone number of principal executive offices)

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

                                  ISSUANCE AGREEMENT
                              (Full title of the plans)

                               F. Richard Nichol, Ph.D.
                        President and Chief Executive Officer
                                    CoCensys, Inc.
                                 213 Technology Drive
                               Irvine, California 92718
              (Name, address, including zip code, and telephone number,
                      including area code, of agent for service)

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

                                      Copies to:
                               Alan C. Mendelson, Esq.
                                  Cooley Godward LLP
                                Five Palo Alto Square
                             Palo Alto, California 94306

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

                           CALCULATION OF REGISTRATION FEE

--------------------------------------------------------------------------------
--------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------
                                             PROPOSED MAXIMUM         PROPOSED MAXIMUM
TITLE OF SECURITIES     AMOUNT TO BE        OFFERING PRICE PER       AGGREGATE OFFERING      AMOUNT OF
 TO BE REGISTERED        REGISTERED             SHARE (1)                PRICE (1)        REGISTRATION FEE
------------------------------------------------------------------------------------------------------------
Common Stock (par         21,094                  $6.5625                $138,429.38           $42.00
value $.001)
------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------
--------------------------------------------------------------------------------
--------------------------------------------------------------------------------

(1) Estimated solely for the purpose of calculating the amount of the
    registration fee pursuant to Rule 457(h).  The price per share and
    aggregate offering price are based upon the average of the high and low
    prices of Registrant's Common Stock on February 10, 1997 as reported on the
    Nasdaq National Market.

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

    Approximate date of commencement of proposed sale to the public:  As soon
as practicable after this Registration Statement becomes effective.
ITEM 3.  INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

    The following documents filed by CoCensys, Inc., a Delaware corporation
(the "Company") with the Securities and Exchange Commission are incorporated by
reference into this Registration Statement:

         (a)  The Company's annual report on Form 10-K, as amended by form
10-K/A for the year ended December 31, 1995.

    (b)  The Company's quarterly reports on Form 10-Q for the quarters ended
March 31, June 30 and September 30, 1996.

    (c)  The Company's current report on Form 8-K, filed January 5, 1996.

    (d)  The description of the Company's Common Stock contained in the
Company's registration statement on Form 8-A filed December 10, 1992.

    (e)  The description of the Company's Preferred Share Purchase Rights
contained in the Company's registration statement on form 8-A filed May 16,
1995.

    All reports and other documents subsequently filed by the Company pursuant
to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act prior to the filing
of a post-effective amendment which indicates that all securities offered have
been sold or which deregisters all securities then remaining unsold, shall be
deemed to be incorporated by reference herein and to be a part of this
registration statement 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

    Not Applicable.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS

    Under Section 145 of the Delaware General Corporation Law, the Company has
broad powers to indemnify its directors and officers against liabilities they
may incur in such capacities, including liabilities under the Securities Act.
The Company's Bylaws require the Company to indemnify its directors and
executive officers, and permit the Company to indemnify its other officers,
employees and other agents, to the fullest extent permitted by Delaware law;
provided, however, that the Company may limit the extent of such indemnification
by individual contracts with its directors and executive officers; and provided
further, that the Company shall not be required to indemnify any director or
executive officer in connection with any proceeding (or part thereof) initiated
by such person or any proceeding by such person against the Company or its
directors, officers, employees or other agents unless (i) such indemnification
is expressly required to be made by law, (ii) the proceeding was authorized by
the Board of Directors of the Company, or (iii) such indemnification is provided
by the Company, in its sole discretion, pursuant to the powers vested in the
Company under the Delaware General Corporation Law.  The Bylaws also require the
Company to advance, prior to the final disposition of any proceeding, promptly
following request therefor, all expenses incurred by any director or executive
officer in connection with such proceeding, upon receipt of an undertaking by or
on behalf of such person to repay said amounts if it should be determined
ultimately that such person is not entitled to be indemnified under the
Company's Bylaws or otherwise.

    The Company has entered into indemnity agreements with each of its
directors and executive officers.  Such indemnity agreements contain provisions
which are in some respects broader than the specific indemnification provisions
contained in Delaware law.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED

    Not Applicable.

                                          2.
ITEM 8.  EXHIBITS

EXHIBIT
NUMBER

5        Opinion of Cooley Godward LLP

23.1     Consent of Ernst & Young LLP

23.2     Consent of Cooley Godward LLP is contained in Exhibit 5 to this
         Registration Statement.

99.1     Issuance Agreement

ITEM 9.  UNDERTAKINGS

    1.   The undersigned registrant hereby undertakes:

         (a)  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;

          (ii)     To reflect in the prospectus any facts or events arising
after the effective date of the 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 the registration
statement.

         (iii)     To include any material information with respect to the plan
of distribution not previously disclosed in the registration statement or any
material change to such information in the registration statement;

    PROVIDED, HOWEVER, that paragraphs (a)(i) and (a)(ii) do not apply if the
registration statement is on Form S-3 or Form S-8 and the information required
to be included in a post-effective amendment by those paragraphs is contained in
periodic reports filed by the issuer pursuant to section 13 or section 15(d) of
the Exchange Act that are incorporated by reference in the registration
statement.

         (b)  That, for the purpose of determining any liability under the
Securities Act, each such post-effective amendment shall be deemed to be a new
registration statement relating to the securities offered herein, and the
offering of such securities at that time shall be deemed to be the initial bona
fide offering thereof.

         (c)  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.

    2.   The undersigned registrant hereby undertakes that, for purposes of
determining any liability under the Securities Act, each filing of the
registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
Exchange Act that is incorporated by reference in the Registration Statement
shall be deemed to be a new registration statement relating to the securities
offered herein, and the offering of such securities at that time shall be deemed
to be the initial bona fide offering thereof.

                                          3.
3.   Insofar as indemnification for liabilities arising under the
Securities Act may be permitted to directors, officers and controlling persons
of the registrant pursuant to the foregoing provisions, 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
Securities 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 Securities
Act and will be governed by the final adjudication of such issue.

                                          4.
SIGNATURES

    THE REGISTRANT.  Pursuant to the requirements of the Securities Act of
1933, as amended, 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 Irvine, State of
California, on February 12, 1997.

                                       COCENSYS, INC.

                                         /s/ F. Richard Nichol
                                       ----------------------------------------
                                       F. Richard Nichol
                                       President and
                                       Chief Executive Officer

                                  POWER OF ATTORNEY

    KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature
appears below constitutes and appoints F. RICHARD NICHOL and PETER E. JANSEN and
each or any one of them, his true and lawful attorney-in-fact and agent, with
full power of substitution and resubstitution, for him and in his name, place
and stead, in any and all capacities, to sign any and all amendments (including
post-effective amendments) to this Registration Statement, and to file the same,
with all exhibits thereto, and other documents in connection therewith, with the
Securities and Exchange Commission, granting unto said attorneys-in-fact and
agents, and each of them, full power and authority to do and perform each and
every act and thing requisite and necessary to be done in connection therewith,
as fully to all intents and purposes as he might or could do in person, hereby
ratifying and confirming all that said attorneys-in-fact and agents, or any of
them, or their or his substitutes or substitute, may lawfully 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/ Lowell E. Sears          Chairman of the Board            February 12, 1997
-------------------------
Lowell E. Sears

/s/ F. Richard Nichol        President and Chief              February 12, 1997
-------------------------    Executive Officer;
F. Richard Nichol, Ph.D.     Director

/s/ Peter E. Jansen          Vice President and Chief         February 12, 1997
-------------------------    Financial Officer
Peter E. Jansen              (Principal Financial Officer)

/s/ Alan C. Mendelson        Director                         February 12, 1997
-------------------------
Alan C. Mendelson

/s/ James C. Blair           Director                         February 12, 1997
-------------------------
James C. Blair, Ph.D.

/s/ Kelvin W. Gee            Director                         February 12, 1997
-------------------------
Kelvin W. Gee, Ph.D.

/s/ Robert G. McNeil         Director                         February 12, 1997
-------------------------
Robert G. McNeil, Ph.D.

/s/ Timothy J. Rink          Director                         February 12, 1997
-------------------------
Timothy J. Rink, M.D., Sc.D.

/s/ Eckard Weber             Director                         February 12, 1997
-------------------------
Eckard Weber, M.D.
EXHIBIT INDEX
EXHIBIT
NUMBER                  DESCRIPTION                   

 5       Opinion of Cooley Godward LLP

23.1     Consent of Ernst & Young LLP

23.2     Consent of Cooley Godward LLP is contained
         in Exhibit 5 to this Registration Statement

99.1     Issuance Agreement