<PAGE>

    AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON NOVEMBER 27, 1996
                              REGISTRATION NO. 333-
-------------------------------------------------------------------------------
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

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

                                     AVIRON
             (Exact name of registrant as specified in its charter)

                          -----------------------------
       DELAWARE                                           77-0309686
(State of Incorporation)                    (I.R.S. Employer Identification No.)

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

                                     AVIRON
                            297 NORTH BERNARDO AVENUE
                            MOUNTAIN VIEW, CA  94043
                                 (415) 919-6500
                            PALO ALTO, CA 94306-2155
          (Address and telephone number of principal executive offices)

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

                           1996 EQUITY INCENTIVE PLAN
                          EMPLOYEE STOCK PURCHASE PLAN
                 1996 NON-EMPLOYEE DIRECTORS' STOCK OPTION PLAN
                             NON-PLAN OPTION GRANTS
                            (Full title of the plans)

                             J. LEIGHTON READ, M.D.
                      CHAIRMAN AND CHIEF EXECUTIVE OFFICER
                                     AVIRON
                            297 NORTH BERNARDO AVENUE
                            MOUNTAIN VIEW, CA  94043
                                 (415) 919-6500
 (Name, address, including zip code, and telephone number, including area code,
                              of agent for service)

                          ----------------------------
                                   Copies to:
                             ALAN C. MENDELSON, ESQ.
                             ROBERT J. BRIGHAM, ESQ.
                               COOLEY GODWARD LLP
                               3000 EL CAMINO REAL
                              FIVE PALO ALTO SQUARE
                            PALO ALTO, CA  94306-2155
                                 (415) 843-5000

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

                         CALCULATION OF REGISTRATION FEE



<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------------------------------
    TITLE OF SECURITIES TO BE          AMOUNT TO BE       PROPOSED MAXIMUM OFFERING     PROPOSED MAXIMUM              AMOUNT OF
           REGISTERED                   REGISTERED           PRICE PER SHARE (1)     AGGREGATE OFFERING PRICE(1)    REGISTRATION FEE
------------------------------------------------------------------------------------------------------------------------------------
<S>                                    <C>                <C>                        <C>                            <C>
Stock Options and Common Stock
($.001 par value)                        2,018,582              $.25 - $7.50                       $11,146,158               $3,378
------------------------------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------------------------------
</TABLE>

(1)  Estimated solely for the purpose of calculating the amount of the
registration fee pursuant to Rule 457(h).  The offering price per share and
aggregate offering price are based upon (a) the weighted average exercise price,
for shares subject to outstanding options granted by Aviron (the "Registrant")
under (i) the Registrant's 1996 Equity Incentive Plan (the "Incentive Plan"),
(ii) the Registrant's 1996 Non-Employee Directors' Stock Option Plan
("Directors' Plan"), and (iii) outstanding stock options granted outside the
Incentive Plan (pursuant to Rule 457(h) under the Securities Act of 1933, as
amended (the "Act")) or (b) the average of the high and low prices of the
Registrant's Common Stock as reported on the Nasdaq Stock Market for November
25, 1996, for (i) shares reserved for future grant pursuant to both the
Incentive Plan and the Directors' Plan, and (ii) shares issuable pursuant to the
Employee Stock Purchase Plan (pursuant to Rule 457(c) under the Act).

The chart below details the calculations of the registration fee:

<TABLE>
<CAPTION>

         TYPE OF SHARES                            NUMBER OF SHARES          OFFERING PRICE PER SHARE    AGGREGATE OFFERING PRICE
         --------------                            ----------------          ------------------------    ------------------------
<S>                                                <C>                       <C>                         <C>
Shares issuable pursuant to outstanding                      490,056                $0.25-$7.50(1)(a)                      432,213
options under 1996 Equity Incentive Plan

Shares issuable pursuant to outstanding                      120,000                      $1.25(1)(a)                      150,000
options granted outside of the 1996 Equity
Incentive Plan

Shares reserved for future issuance                        1,158,526                      $7.50(1)(b)                    8,688,945
pursuant to the 1996 Equity Incentive Plan
and 1996 Non-Employee Directors' Plan

Shares issuable pursuant to the Employee                     250,000                      $7.50(1)(b)                    1,875,000
Stock Purchase Plan

Proposed Maximum Offering Price                                                                                        $11,146,158

Registration Fee                                                                                                            $3,378
</TABLE>

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

<PAGE>

                 INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

     The following documents filed by Aviron (the "Registrant") with the
Securities and Exchange Commission are incorporated by reference into this
Registration Statement:

          (a)  The Registrant's latest annual report on Form 10-K filed pursuant
to Sections 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended
(the "Exchange Act"), or either (1) the Registrant's latest prospectus filed
pursuant to Rule 424(b) under the Securities Act of 1933, as amended (the
"Act"), that contains audited financial statements for the Registrant's latest
fiscal year for which such statements have been filed, or (2) the Registrant's
effective registration statement on Form 10 or 20-F filed under the Exchange Act
containing audited financial statements for the Registrant's latest fiscal year.

          (b)  All other reports filed pursuant to Sections 13(a) or 15(d) of
the Exchange Act since the end of the fiscal year covered by the annual reports,
the prospectus or the registration statement referred to in (a) above.

          (c)  The description of the Registrant's Common Stock which is
contained in the registration statement filed under the Exchange Act, including
any amendment or report filed for the purpose of updating such description.

     All reports and other documents subsequently filed by the Registrant
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.

                            DESCRIPTION OF SECURITIES

     Not applicable.

                     INTERESTS OF NAMED EXPERTS AND COUNSEL

     Not applicable.

                    INDEMNIFICATION OF DIRECTORS AND OFFICERS

     Under Section 145 of the Delaware General Corporation Law, the Registrant
has broad powers to indemnify its directors and officers against liabilities
they may incur in such capacities, including liabilities under the Securities
Act of 1933, as amended (the "Securities Act").  The Registrant's Bylaws also
provide that the Registrant will indemnify its directors and executive officers
and may indemnify its other officers, employees and agents to the fullest extent
permitted by Delaware law.

     The Registrant's Certificate of Incorporation provides for the elimination
of liability for monetary damages for breach of the directors' fiduciary duty of
care to the Registrant and its stockholders.  These provisions do not eliminate
the directors' duty of care and, in appropriate circumstances, equitable
remedies such as injunctive or other forms of  non-monetary relief will remain
available under Delaware law.  In addition, each director will continue to be
subject to  liability for breach of the director's duty of loyalty to the
Registrant, for acts or omissions not in good faith or involving  intentional
misconduct, for knowing violations of law, for any transaction from which the
director derived an improper personal benefit, and for payment of dividends or
approval of stock repurchases or redemptions that are unlawful under Delaware
law.  The provision does not affect a director's responsibilities under any
other laws, such as the federal  securities laws or state or federal
environmental laws.

                                       1.

<PAGE>

                       EXEMPTION FROM REGISTRATION CLAIMED

     Not applicable.

                                    EXHIBITS

EXHIBIT
NUMBER

4.1*      Amended and Restated Certificate of Incorporation of the
          Registrant

4.2*      Bylaws of the Registrant

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

24        Power of Attorney is contained on the signature pages

99.1*     The Registrant's 1996 Equity Incentive Plan.

99.2      Form of Incentive Stock Option under the 1996 Equity Incentive Plan.

99.3      Form of Non-statutory Stock Option under the 1996 Equity Incentive
          Plan.

99.4**    Employee Stock Purchase Plan.

99.5      Employee Stock Purchase Plan Offering Document.

99.6**    1996 Non-Employee Directors' Stock Option Plan

99.7      Form of Non-statutory Stock Option under the 1996 Non-Employee
          Directors' Stock Option Plan.

99.8      Form of Non-statutory Stock Option (Performance-Based) Granted Outside
          the Incentive Plan.

   *      Documents incorporated by reference from the Registrant's Registration
          Statement on Form S-1 (Amendment No. 2, Registration No. 333-05209)
          filed with the SEC on July 16, 1996.

   * *    Documents incorporated by reference from the Registrant's Registration
          Statement on Form S-1 (Registration No. 333-05209) filed with the SEC
          on June 5, 1996.


                                  UNDERTAKINGS

          (d)  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,

                                       2.

<PAGE>

represent a fundamental change in the information set forth in the registration
statement.  Notwithstanding the foregoing, any increase or decrease in volume of
securities offered (if the total dollar value of securities offered would not
exceed that which was registered) and any deviation from the low or high end of
the estimated maximum offering range may be reflected in the form of prospectus
filed with the Commission pursuant to Rule 424(b) (Section 230.424(b) of this
chapter) if, in the aggregate, the changes in volume and price represent no more
than a 20% change in the maximum aggregate offering price set forth in the
"Calculation of Registration Fee" table in the effective 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.

     (e)  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 (and, where applicable, each filing of an employee benefit plan's
annual report pursuant to 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.

     (f)  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.


                                       3.

<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 Mountain View, State of
California, on November 26, 1996.


                                   AVIRON



                                   By  /s/ J. Leighton Read, M.D.
                                     ----------------------------
                                     J. Leighton Read, M.D.
                                     Chairman and Chief Executive Officer



                                POWER OF ATTORNEY


     KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature 
appears below constitutes and appoints J. Leighton Read and Vera Kallmeyer, 
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/ J. Leighton Read, M.D.        Chairman and Chief          November 26, 1996
------------------------------    Executive Officer              
     J. Leighton Read, M.D.


/s/ Vera Kallmeyer, M.D., Ph.D.   Chief Financial Officer     November 26, 1996
------------------------------    and Vice President,            
Vera Kallmeyer, M.D., Ph.D.       Corporate Development

/s/ Reid W. Dennis                Director                    November 26, 1996
------------------------------                                   
     Reid W. Dennis

                                  Director                               , 1996
------------------------------                                ----------
     Paul H. Klingenstein

/s/ Jane E. Shaw, Ph.D.           Director                    November 26, 1996
------------------------------                                
     Jane E. Shaw, Ph.D.


                                       4.

<PAGE>

/s/ L. James Strand, M.D.         Director                    November 26, 1996
------------------------------                                   
     L. James Strand, M.D.



/s/ Bernard Roizman, Sc.D.        Director                    November 26, 1996
------------------------------                                  
     Bernard Roizman, Sc.D.


                                       5.

<PAGE>


                                 EXHIBIT INDEX


EXHIBIT                 DESCRIPTION                                
NUMBER                                                             

4.1*      Amended and Restated Certificate of Incorporation
          of the Registrant

4.2*      Bylaws of the Registrant

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

24        Power of Attorney is contained on the signature
          pages

99.1**    The Registrant's 1996 Equity Incentive Plan.

99.2      Form of Incentive Stock Option under the 1996
          Equity Incentive Plan.

99.3      Form of Non-statutory Stock Option under the 1996
          Equity Incentive Plan.

99.4**    Employee Stock Purchase Plan.

99.5      Employee Stock Purchase Plan Offering Document.

99.6**    1996 Non-Employee Directors' Stock Option Plan.

99.7      Form of Non-statutory Stock Option under the 1996
          Non-Employee Directors' Stock Option Plan.

99.8      Form of Non-statutory Stock Option (Performance-
          Based) Granted Outside the Incentive Plan.

     *    Documents incorporated by reference from the Registrant's Registration
          Statement on Form S-1 (Amendment No. 2, Registration No. 333-05209)
          filed with the SEC on July 16, 1996.

     **   Documents incorporated by reference from the Registrant's Registration
          Statement on Form S-1 (File No. 333-05209) filed with the SEC on June
          5, 1996.

                                       6.
[{"type": "S-8", "sequence": "1", "description": "S-8", "secsgml_size_bytes": 21132}]
{"company-data": {"conformed-name": "AVIRON", "cik": "0000949173", "assigned-sic": "2836", "irs-number": "770309686", "state-of-incorporation": "CA", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-17029", "film-number": "96673959"}, "business-address": {"street1": "297 N BERNARDO AVE", "city": "MOUNTAIN VIEW", "state": "CA", "zip": "94043", "phone": "4159196500"}, "mail-address": {"street1": "297 NORTH BERNARDO AVE", "city": "MOUNTAIN VIEW", "state": "CA", "zip": "94043"}}
AS FILED WITH THE SECURITIES AND EXCHANGE COMMISSION ON NOVEMBER 27, 1996
                              REGISTRATION NO. 333-
-------------------------------------------------------------------------------
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

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

                                     AVIRON
             (Exact name of registrant as specified in its charter)

                          -----------------------------
       DELAWARE                                           77-0309686
(State of Incorporation)                    (I.R.S. Employer Identification No.)

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

                                     AVIRON
                            297 NORTH BERNARDO AVENUE
                            MOUNTAIN VIEW, CA  94043
                                 (415) 919-6500
                            PALO ALTO, CA 94306-2155
          (Address and telephone number of principal executive offices)

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

                           1996 EQUITY INCENTIVE PLAN
                          EMPLOYEE STOCK PURCHASE PLAN
                 1996 NON-EMPLOYEE DIRECTORS' STOCK OPTION PLAN
                             NON-PLAN OPTION GRANTS
                            (Full title of the plans)

                             J. LEIGHTON READ, M.D.
                      CHAIRMAN AND CHIEF EXECUTIVE OFFICER
                                     AVIRON
                            297 NORTH BERNARDO AVENUE
                            MOUNTAIN VIEW, CA  94043
                                 (415) 919-6500
 (Name, address, including zip code, and telephone number, including area code,
                              of agent for service)

                          ----------------------------
                                   Copies to:
                             ALAN C. MENDELSON, ESQ.
                             ROBERT J. BRIGHAM, ESQ.
                               COOLEY GODWARD LLP
                               3000 EL CAMINO REAL
                              FIVE PALO ALTO SQUARE
                            PALO ALTO, CA  94306-2155
                                 (415) 843-5000

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

                         CALCULATION OF REGISTRATION FEE
------------------------------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------------------------------
    TITLE OF SECURITIES TO BE          AMOUNT TO BE       PROPOSED MAXIMUM OFFERING     PROPOSED MAXIMUM              AMOUNT OF
           REGISTERED                   REGISTERED           PRICE PER SHARE (1)     AGGREGATE OFFERING PRICE(1)    REGISTRATION FEE
------------------------------------------------------------------------------------------------------------------------------------
Stock Options and Common Stock
($.001 par value)                        2,018,582              $.25 - $7.50                       $11,146,158               $3,378
------------------------------------------------------------------------------------------------------------------------------------
------------------------------------------------------------------------------------------------------------------------------------
(1)  Estimated solely for the purpose of calculating the amount of the
registration fee pursuant to Rule 457(h).  The offering price per share and
aggregate offering price are based upon (a) the weighted average exercise price,
for shares subject to outstanding options granted by Aviron (the "Registrant")
under (i) the Registrant's 1996 Equity Incentive Plan (the "Incentive Plan"),
(ii) the Registrant's 1996 Non-Employee Directors' Stock Option Plan
("Directors' Plan"), and (iii) outstanding stock options granted outside the
Incentive Plan (pursuant to Rule 457(h) under the Securities Act of 1933, as
amended (the "Act")) or (b) the average of the high and low prices of the
Registrant's Common Stock as reported on the Nasdaq Stock Market for November
25, 1996, for (i) shares reserved for future grant pursuant to both the
Incentive Plan and the Directors' Plan, and (ii) shares issuable pursuant to the
Employee Stock Purchase Plan (pursuant to Rule 457(c) under the Act).

The chart below details the calculations of the registration fee:
TYPE OF SHARES                            NUMBER OF SHARES          OFFERING PRICE PER SHARE    AGGREGATE OFFERING PRICE
         --------------                            ----------------          ------------------------    ------------------------
Shares issuable pursuant to outstanding                      490,056                $0.25-$7.50(1)(a)                      432,213
options under 1996 Equity Incentive Plan

Shares issuable pursuant to outstanding                      120,000                      $1.25(1)(a)                      150,000
options granted outside of the 1996 Equity
Incentive Plan

Shares reserved for future issuance                        1,158,526                      $7.50(1)(b)                    8,688,945
pursuant to the 1996 Equity Incentive Plan
and 1996 Non-Employee Directors' Plan

Shares issuable pursuant to the Employee                     250,000                      $7.50(1)(b)                    1,875,000
Stock Purchase Plan

Proposed Maximum Offering Price                                                                                        $11,146,158

Registration Fee                                                                                                            $3,378
Approximate date of commencement of proposed sale to the public:  As soon as
practicable after this Registration Statement becomes effective.
INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE

     The following documents filed by Aviron (the "Registrant") with the
Securities and Exchange Commission are incorporated by reference into this
Registration Statement:

          (a)  The Registrant's latest annual report on Form 10-K filed pursuant
to Sections 13(a) or 15(d) of the Securities Exchange Act of 1934, as amended
(the "Exchange Act"), or either (1) the Registrant's latest prospectus filed
pursuant to Rule 424(b) under the Securities Act of 1933, as amended (the
"Act"), that contains audited financial statements for the Registrant's latest
fiscal year for which such statements have been filed, or (2) the Registrant's
effective registration statement on Form 10 or 20-F filed under the Exchange Act
containing audited financial statements for the Registrant's latest fiscal year.

          (b)  All other reports filed pursuant to Sections 13(a) or 15(d) of
the Exchange Act since the end of the fiscal year covered by the annual reports,
the prospectus or the registration statement referred to in (a) above.

          (c)  The description of the Registrant's Common Stock which is
contained in the registration statement filed under the Exchange Act, including
any amendment or report filed for the purpose of updating such description.

     All reports and other documents subsequently filed by the Registrant
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.

                            DESCRIPTION OF SECURITIES

     Not applicable.

                     INTERESTS OF NAMED EXPERTS AND COUNSEL

     Not applicable.

                    INDEMNIFICATION OF DIRECTORS AND OFFICERS

     Under Section 145 of the Delaware General Corporation Law, the Registrant
has broad powers to indemnify its directors and officers against liabilities
they may incur in such capacities, including liabilities under the Securities
Act of 1933, as amended (the "Securities Act").  The Registrant's Bylaws also
provide that the Registrant will indemnify its directors and executive officers
and may indemnify its other officers, employees and agents to the fullest extent
permitted by Delaware law.

     The Registrant's Certificate of Incorporation provides for the elimination
of liability for monetary damages for breach of the directors' fiduciary duty of
care to the Registrant and its stockholders.  These provisions do not eliminate
the directors' duty of care and, in appropriate circumstances, equitable
remedies such as injunctive or other forms of  non-monetary relief will remain
available under Delaware law.  In addition, each director will continue to be
subject to  liability for breach of the director's duty of loyalty to the
Registrant, for acts or omissions not in good faith or involving  intentional
misconduct, for knowing violations of law, for any transaction from which the
director derived an improper personal benefit, and for payment of dividends or
approval of stock repurchases or redemptions that are unlawful under Delaware
law.  The provision does not affect a director's responsibilities under any
other laws, such as the federal  securities laws or state or federal
environmental laws.

                                       1.
EXEMPTION FROM REGISTRATION CLAIMED

     Not applicable.

                                    EXHIBITS

EXHIBIT
NUMBER

4.1*      Amended and Restated Certificate of Incorporation of the
          Registrant

4.2*      Bylaws of the Registrant

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

24        Power of Attorney is contained on the signature pages

99.1*     The Registrant's 1996 Equity Incentive Plan.

99.2      Form of Incentive Stock Option under the 1996 Equity Incentive Plan.

99.3      Form of Non-statutory Stock Option under the 1996 Equity Incentive
          Plan.

99.4**    Employee Stock Purchase Plan.

99.5      Employee Stock Purchase Plan Offering Document.

99.6**    1996 Non-Employee Directors' Stock Option Plan

99.7      Form of Non-statutory Stock Option under the 1996 Non-Employee
          Directors' Stock Option Plan.

99.8      Form of Non-statutory Stock Option (Performance-Based) Granted Outside
          the Incentive Plan.

   *      Documents incorporated by reference from the Registrant's Registration
          Statement on Form S-1 (Amendment No. 2, Registration No. 333-05209)
          filed with the SEC on July 16, 1996.

   * *    Documents incorporated by reference from the Registrant's Registration
          Statement on Form S-1 (Registration No. 333-05209) filed with the SEC
          on June 5, 1996.

                                  UNDERTAKINGS

          (d)  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,

                                       2.
represent a fundamental change in the information set forth in the registration
statement.  Notwithstanding the foregoing, any increase or decrease in volume of
securities offered (if the total dollar value of securities offered would not
exceed that which was registered) and any deviation from the low or high end of
the estimated maximum offering range may be reflected in the form of prospectus
filed with the Commission pursuant to Rule 424(b) (Section 230.424(b) of this
chapter) if, in the aggregate, the changes in volume and price represent no more
than a 20% change in the maximum aggregate offering price set forth in the
"Calculation of Registration Fee" table in the effective 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.

     (e)  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 (and, where applicable, each filing of an employee benefit plan's
annual report pursuant to 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.

     (f)  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.

                                       3.
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 Mountain View, State of
California, on November 26, 1996.

                                   AVIRON

                                   By  /s/ J. Leighton Read, M.D.
                                     ----------------------------
                                     J. Leighton Read, M.D.
                                     Chairman and Chief Executive Officer

                                POWER OF ATTORNEY

     KNOW ALL PERSONS BY THESE PRESENTS, that each person whose signature 
appears below constitutes and appoints J. Leighton Read and Vera Kallmeyer, 
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/ J. Leighton Read, M.D.        Chairman and Chief          November 26, 1996
------------------------------    Executive Officer              
     J. Leighton Read, M.D.

/s/ Vera Kallmeyer, M.D., Ph.D.   Chief Financial Officer     November 26, 1996
------------------------------    and Vice President,            
Vera Kallmeyer, M.D., Ph.D.       Corporate Development

/s/ Reid W. Dennis                Director                    November 26, 1996
------------------------------                                   
     Reid W. Dennis

                                  Director                               , 1996
------------------------------                                ----------
     Paul H. Klingenstein

/s/ Jane E. Shaw, Ph.D.           Director                    November 26, 1996
------------------------------                                
     Jane E. Shaw, Ph.D.

                                       4.
/s/ L. James Strand, M.D.         Director                    November 26, 1996
------------------------------                                   
     L. James Strand, M.D.

/s/ Bernard Roizman, Sc.D.        Director                    November 26, 1996
------------------------------                                  
     Bernard Roizman, Sc.D.

                                       5.
EXHIBIT INDEX

EXHIBIT                 DESCRIPTION                                
NUMBER                                                             

4.1*      Amended and Restated Certificate of Incorporation
          of the Registrant

4.2*      Bylaws of the Registrant

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

24        Power of Attorney is contained on the signature
          pages

99.1**    The Registrant's 1996 Equity Incentive Plan.

99.2      Form of Incentive Stock Option under the 1996
          Equity Incentive Plan.

99.3      Form of Non-statutory Stock Option under the 1996
          Equity Incentive Plan.

99.4**    Employee Stock Purchase Plan.

99.5      Employee Stock Purchase Plan Offering Document.

99.6**    1996 Non-Employee Directors' Stock Option Plan.

99.7      Form of Non-statutory Stock Option under the 1996
          Non-Employee Directors' Stock Option Plan.

99.8      Form of Non-statutory Stock Option (Performance-
          Based) Granted Outside the Incentive Plan.

     *    Documents incorporated by reference from the Registrant's Registration
          Statement on Form S-1 (Amendment No. 2, Registration No. 333-05209)
          filed with the SEC on July 16, 1996.

     **   Documents incorporated by reference from the Registrant's Registration
          Statement on Form S-1 (File No. 333-05209) filed with the SEC on June
          5, 1996.

                                       6.