<PAGE>

   As filed with the Securities and Exchange Commission on December 20, 1995

                                                 Registration No. 33-
                                                                     -----------

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

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                            ------------------------
                               CHIRON CORPORATION
               (EXACT NAME OF ISSUER AS SPECIFIED IN ITS CHARTER)

                Delaware                             94-2754624
     (State or other jurisdiction of              (I.R.S. Employer
     incorporation or organization)              Identification No.)
                  4560 Horton St., Emeryville, California 94608
                                 (510) 655-8730
          (Address, including zip code, and telephone number, including
             area code, of registrant's principal executive offices)

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

                   Viagene, Inc. Employee Stock Purchase Plan
                            (Full title of the plan)

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

                            EDWARD E. PENHOET, PH.D.
                      President and Chief Executive Officer
                               CHIRON CORPORATION
                4560 Horton Street, Emeryville, California 94608
                                 (510) 655-8730
            (Name, address, including zip code, and telephone number,
                   including area code, of agent for service)

                         CALCULATION OF REGISTRATION FEE

<TABLE>
<CAPTION>
- -----------------------------------------------------------------------------------------------------------------------------
- -----------------------------------------------------------------------------------------------------------------------------
  Title of Securities                                  Proposed Maximum           Proposed Maximum          Amount of
   to be Registered       Amount to be Registered   Offering Price Per Share  Aggregate Offering Price    Registration Fee
   ----------------       -----------------------   ------------------------  ------------------------    ----------------
<S>                       <C>                       <C>                       <C>                         <C>
Common Stock, $0.01 par           7,200 (1)              $98.25 (2)                $707,400 (2)                   $244
value (Viagene, Inc.
Employee Stock Purchase
Plan)
- -----------------------------------------------------------------------------------------------------------------------------
- -----------------------------------------------------------------------------------------------------------------------------
</TABLE>

(1)  This Registration Statement shall also cover any additional shares of
     Common Stock which become issuable under the Viagene, Inc. 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 the purposes of this offering under Rule 457(h) of
     the Securities Act of 1933 on the basis of the average of the high and low
     selling prices per share of Common Stock of Chiron Corporation on December
     18, 1995, as reported by the NASDAQ National Market System.

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>

                                     PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

     Chiron Corporation (the "Registrant") files this Registration Statement
with the Securities and Exchange Commission (the "Commission") on Form S-8 to
register 7,200 shares of Chiron Common Stock authorized for issuance pursuant
to outstanding rights under the Viagene, Inc. Employee Stock Purchase Plan,
assumed by the Registrant at the effective time of the merger of Viagene, Inc.
with and into a wholly-owned subsidiary of the Registrant, following which
Viagene, Inc. became a wholly-owned subsidiary of the Registrant.

ITEM 3.  INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE.

     The Registrant hereby incorporates by reference into this Registration
Statement the following documents previously filed with the Commission:

     (a)  The Registrant's Annual Report on Form 10-K for the year ended
December 31, 1994 filed pursuant to Section 13(a) of the Securities Exchange Act
of 1934 (the "1934 Act");

     (b)  Amendment Number 1 to Registrant's Annual Report on Form 10-K for the
year ended December 31, 1994, dated April 24, 1995;

     (c)  Amendment Number 2 to the Registrant's Annual Report on Form 10-K for
the year ended December 31, 1994, dated December 11, 1995;

     (d)  The Registrant's Quarterly Report on Form 10-Q for the quarter ended
April 2, 1995 filed pursuant to Section 13 of the 1934 Act;

     (e)  Amendment Number 1 to Registrant's Quarterly Report on Form 10-Q for
the quarter ended April 2, 1995, dated July 28, 1995;

     (f)  The Registrant's Quarterly Report on Form 10-Q for the quarter ended
July 2, 1995 filed pursuant to Section 13 of the 1934 Act;

     (g)  The Registrant's Quarterly Report on Form 10-Q for the quarter ended
October 2, 1995 filed pursuant to Section 13 of the 1934 Act;

     (h)  The Registrant's Current Reports on Form 8-K and 8-K/A dated January
4, 1995 as amended on March 17, 1995;

     (i)  The Registrant's Current Report on Form 8-K dated March 6, 1995;

     (j)  The Registrant's Current Report on Form 8-K dated March 10, 1995;

     (k)  The Registrant's Current Report on Form 8-K dated April 24, 1995;


                                      II-1
<PAGE>

     (l)  The Registrant's Current Report on Form 8-K dated May 5, 1995;

     (m)  The Registrant's Current Report on Form 8-K and 8-K/A dated September
29, 1995, as amended on November 13, 1995; and

     (n)  The description of Registrant's Common Stock contained in its
Registration Statement on Form 8-A filed with the Commission on August 28, 1984.



     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 filing of such documents.

ITEM 4.  DESCRIPTION OF SECURITIES.

     Not applicable.

ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.

     William G. Green, who has provided an opinion to the Registrant on the
validity of the securities being registered which is Exhibit 5 to this
registration statement, is Senior Vice President, General Counsel and Secretary
of the Registrant.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

     Section 145 of the General Corporation Law of the State of Delaware and the
Bylaws of the Registrant contain provisions covering indemnification of
corporate directors, officers and employees under certain conditions and subject
to certain limitations.

     In addition, the Registrant has entered into supplemental indemnification
agreements with its directors which broaden the scope of indemnity beyond that
expressly provided by the Bylaws or the Delaware General Corporation Law.  These
supplemental contracts are permissible under the Delaware General Corporation
Law and have been approved by the Registrant's stockholders.  Accordingly, the
indemnification agreements with directors (i) confirm the present indemnity
provided to them by the Registrant's Bylaws and give them assurance that this
indemnity will continue to be provided despite future changes in the Bylaws, and
(ii) provide that, in addition, the directors shall be indemnified to the
fullest possible extent permitted by law against all expenses (including
attorneys' fees), judgments, fines and settlement amounts, incurred or paid by
them in any action or proceeding, including any action by or in the right of the
Registrant, on


                                      II-2
<PAGE>


account of their service as a director or officer of the Registrant, or as a
director or officer of any subsidiary of the Registrant, or as a director,
officer or similar official of any other company or enterprise when they are
serving in such capacities at the request of the Registrant.  The
indemnification agreements further provide that expenses incurred by a director
in such cases shall be paid in advance, subject to the director's obligation to
reimburse the Registrant in the event it ultimately determines that the director
is not entitled to be indemnified for such expenses under any of the provisions
of the indemnification agreement.  However, no indemnity will be provided to any
director under the agreements as described in clause (ii) of the third sentence
of this paragraph on account of conduct which is finally adjudged to be
knowingly fraudulent, deliberately dishonest or to constitute willful
misconduct.  In addition, no indemnification will be provided if a final court
adjudication shall determine that such indemnification is not lawful, or in
respect to any suit in which judgment is rendered against a director for an
accounting of profits made from a purchase or sale of securities of the
Registrant in violation of Section 16(b) of the 1934 Act, as amended, or of any
similar statutory provision, or on account of any remuneration paid to a
director which is finally adjudged to have been paid in violation of law.  The
indemnification agreements also contain provisions designed to protect the
Registrant from unreasonable settlements or redundant legal expenditures.

     The Registrant maintains liability insurance for each of its directors and
officers which provides for coverage for certain liabilities for which
indemnification by the Registrant may not be permissible under applicable law
and public policy, including liabilities under the Securities Act of 1933, as
amended.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.

     Not applicable.

ITEM 8.  EXHIBITS.

EXHIBIT NUMBER      EXHIBIT
- --------------      -------

          4.01      Rights Agreement, dated as of August 25, 1994, between the
                    Company and Continental Stock Transfer & Trust Company,
                    which includes the Certificate of Designations for the
                    Series A Junior Participating Preferred Stock as Exhibit A,
                    the form of Right Certificate as Exhibit B and the Summary
                    of Rights to Purchase Preferred Shares as Exhibit C,
                    incorporated by reference to Exhibit 4.04 of the
                    Registrant's current report on Form 8-K dated August 25,
                    1994.

          4.02      Amendment No. 1 to Rights Agreement dated as of November 20,
                    1994, between Chiron Corporation and Continental Stock
                    Transfer &


                                      II-3
<PAGE>


                    Trust Company, incorporated by reference to Exhibit 4.05 of
                    the Registrant's current report on Form 8-K, dated November
                    20, 1994.

          5         Opinion of William G. Green.
          23.1      Consent of KPMG Peat Marwick LLP, Independent Auditors,
                    relating to the 1994 consolidated financial statements of
                    Chiron Corporation and subsidiaries.
          23.2      Consent of Ernst & Young LLP, Independent Auditors, relating
                    to the 1993 and 1992 consolidated financial statements of
                    Chiron Corporation.
          23.3      Consent of Ernst & Young LLP, Independent Auditors, relating
                    to the consolidated financial statements of Ciba Corning
                    Diagnostics Corp.
          23.4      Consent of KPMG Peat Marwick LLP, Independent Auditors,
                    relating to the financial statements of The Biocine Company.
          23.5      Consent of Reconta Ernst & Young, Independent Auditors,
                    relating to the consolidated financial statements of JV Vax
                    B.V.
          23.6      Consent of Ernst & Young LLP, Independent Auditors,
                    relating to the financial statements of Viagene, Inc.
          23.7      Consent of William G. Green is contained in Exhibit 5.
          24        Power of Attorney.  Reference is made to pages II-6 and II-7
                    of this Registration Statement.
          99.1      Viagene, Inc. Employee Stock Purchase Plan.

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 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, and (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 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 the registration statement; and (2) that for the
purpose of determining any liability under the Securities Act of 1933 each such
post-effective amendment shall 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; (3)
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.

     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


                                      II-4
<PAGE>


reference into the Registration Statement shall 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 foregoing provisions, or otherwise,
the Registrant has been informed that in the opinion of the Securities and
Exchange 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.


                                      II-5
<PAGE>

                                   SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the Registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized in the City of Emeryville, State of California, on the 19th day of
December, 1995.


                                   CHIRON CORPORATION

                                   By /s/ Edward E. Penhoet
                                      ----------------------------------
                                      Edward E. Penhoet
                                      President and Chief Executive Officer


                                POWER OF ATTORNEY

     KNOW ALL PERSONS BY THESE PRESENTS, that the undersigned officers and
directors of Chiron Corporation, a Delaware corporation, do hereby constitute
and appoint Edward E. Penhoet and William J. Rutter, and each of them, the
lawful attorneys and agents or attorney and agent with full power and authority
to do any and all acts and things and to execute any and all instruments which
said attorneys and agents, and any one of them, determine may be necessary or
advisable or required to enable said corporation to comply with the Securities
Act of 1933, as amended, and any rules or regulations or requirements of the
Securities and Exchange Commission in connection with this Registration
Statement.  Without limiting the generality of the foregoing power and
authority, the powers granted include the power and authority to sign the names
of the undersigned officers and directors in the capacities indicated below this
Registration Statement, to any and all amendments, both pre-effective and post-
effective, and supplements to this Registration Statement, and to any and all
instruments or documents filed as part of or in conjunction with this
Registration Statement or amendments or supplements thereof, and each of the
undersigned hereby ratifies and confirms all that said attorneys and agents, or
any one of them shall do or cause to be done by virtue hereof.  This Power of
Attorney may be signed in several counterparts.

     IN WITNESS WHEREOF, each of the undersigned has executed this Power of
Attorney as of the date indicated.


                                      II-6
<PAGE>

     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>
<CAPTION>
SIGNATURE                            TITLE                            DATE
<S>                                  <C>                              <C>
/s/ Edward E. Penhoet, Ph.D.         President, Chief Executive       December 19, 1995
- --------------------------------     Officer and Director (Principal
(Edward E. Penhoet, Ph.D.)           Executive Officer)

/s/ William J. Rutter, Ph.D.         Chairman of the Board            December 19, 1995
- --------------------------------
(William J. Rutter, Ph.D.)

/s/ Dennis L. Winger                 Senior Vice President, Finance   December 19, 1995
- --------------------------------     and Administration, Chief
(Dennis L. Winger)                   Financial Officer (Principal
                                     Financial and Accounting
                                     Officer)

/s/ Gilbert F. Amelio, Ph.D.         Director                         December 19, 1995
- --------------------------------
(Gilbert F. Amelio, Ph.D.)

/s/ Lewis W. Coleman                 Director
- --------------------------------
(Lewis W. Coleman)

/s/ Pierre E. Douaze                 Director                         December 19, 1995
- --------------------------------
(Pierre E. Douaze)

/s/ Donald A. Glaser, Ph.D.          Director                         December 19, 1995
- --------------------------------
(Donald A. Glaser, Ph.D.)

/s/ Alex Krauer, Ph.D.               Director                         December 19, 1995
- --------------------------------
(Alex Krauer, Ph.D.)

/s/ Francois L'Eplattenier, Ph.D     Director                         December 19, 1995
- --------------------------------
(Francois L'Eplattenier, Ph.D.)

/s/ Henri Schramek, Ph.D.            Director                         December 19, 1995
- --------------------------------
(Henri Schramek, Ph.D.)

/s/ Jack W. Schuler                  Director                         December 19, 1995
- --------------------------------
(Jack W. Schuler)

/s/ Pieter J. Strijkert, Ph.D.       Director                         December 19, 1995
- --------------------------------
(Pieter J. Strijkert, Ph.D.)
</TABLE>


                                      II-7
<PAGE>


                       SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C.  20549


                                    EXHIBITS
                                       TO
                                    FORM S-8
                                      UNDER
                             SECURITIES ACT OF 1933

                               CHIRON CORPORATION

<PAGE>

                                  EXHIBIT INDEX



EXHIBIT NUMBER      EXHIBIT
- --------------      -------

          4.01      Rights Agreement, dated as of August 25, 1994, between the
                    Company and Continental Stock Transfer & Trust Company,
                    which includes the Certificate of Designations for the
                    Series A Junior Participating Preferred Stock as Exhibit A,
                    the form of Right Certificate as Exhibit B and the Summary
                    of Rights to Purchase Preferred Shares as Exhibit C,
                    incorporated by reference to Exhibit 4.04 of the
                    Registrant's current report on Form 8-K dated August 25,
                    1994.

          4.02      Amendment No. 1 to Rights Agreement dated as of November 20,
                    1994, between Chiron Corporation and Continental Stock
                    Transfer & Trust Company, incorporated by reference to
                    Exhibit 4.05 of the Registrant's current report on Form 8-K,
                    dated November 20, 1994.

          5         Opinion of William G. Green.
          23.1      Consent of KPMG Peat Marwick LLP, Independent Auditors,
                    relating to the 1994 consolidated financial statements of
                    Chiron Corporation and subsidiaries.
          23.2      Consent of Ernst & Young LLP, Independent Auditors, relating
                    to the 1993 and 1992 consolidated financial statements of
                    Chiron Corporation.
          23.3      Consent of Ernst & Young LLP, Independent Auditors, relating
                    to the consolidated financial statements of Ciba Corning
                    Diagnostics Corp.
          23.4      Consent of KPMG Peat Marwick LLP, Independent Auditors,
                    relating to the financial statements of The Biocine Company.
          23.5      Consent of Reconta Ernst & Young, Independent Auditors,
                    relating to the consolidated financial statements of JV Vax
                    B.V.
          23.6      Consent of Ernst & Young LLP, Independent Auditors,
                    relating to the financial statements of Viagene, Inc.
          23.7      Consent of William G. Green is contained in Exhibit 5.
          24        Power of Attorney.  Reference is made to pages II-6 and II-7
                    of this Registration Statement.
          99.1      Viagene, Inc. Employee Stock Purchase Plan.
[{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 24824}]
{"company-data": {"conformed-name": "CHIRON CORP", "cik": "0000706539", "assigned-sic": "2835", "irs-number": "942754624", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "033-65177", "film-number": "95602919"}, "business-address": {"street1": "4560 HORTON ST", "city": "EMERYVILLE", "state": "CA", "zip": "94608", "phone": "5106558730"}}
As filed with the Securities and Exchange Commission on December 20, 1995

                                                 Registration No. 33-
                                                                     -----------

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

                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549

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

                                    FORM S-8
                             REGISTRATION STATEMENT
                                      UNDER
                           THE SECURITIES ACT OF 1933
                            ------------------------
                               CHIRON CORPORATION
               (EXACT NAME OF ISSUER AS SPECIFIED IN ITS CHARTER)

                Delaware                             94-2754624
     (State or other jurisdiction of              (I.R.S. Employer
     incorporation or organization)              Identification No.)
                  4560 Horton St., Emeryville, California 94608
                                 (510) 655-8730
          (Address, including zip code, and telephone number, including
             area code, of registrant's principal executive offices)

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

                   Viagene, Inc. Employee Stock Purchase Plan
                            (Full title of the plan)

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

                            EDWARD E. PENHOET, PH.D.
                      President and Chief Executive Officer
                               CHIRON CORPORATION
                4560 Horton Street, Emeryville, California 94608
                                 (510) 655-8730
            (Name, address, including zip code, and telephone number,
                   including area code, of agent for service)

                         CALCULATION OF REGISTRATION FEE
- -----------------------------------------------------------------------------------------------------------------------------
- -----------------------------------------------------------------------------------------------------------------------------
  Title of Securities                                  Proposed Maximum           Proposed Maximum          Amount of
   to be Registered       Amount to be Registered   Offering Price Per Share  Aggregate Offering Price    Registration Fee
   ----------------       -----------------------   ------------------------  ------------------------    ----------------
Common Stock, $0.01 par           7,200 (1)              $98.25 (2)                $707,400 (2)                   $244
value (Viagene, Inc.
Employee Stock Purchase
Plan)
- -----------------------------------------------------------------------------------------------------------------------------
- -----------------------------------------------------------------------------------------------------------------------------
(1)  This Registration Statement shall also cover any additional shares of
     Common Stock which become issuable under the Viagene, Inc. 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 the purposes of this offering under Rule 457(h) of
     the Securities Act of 1933 on the basis of the average of the high and low
     selling prices per share of Common Stock of Chiron Corporation on December
     18, 1995, as reported by the NASDAQ National Market System.

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.

                            ------------------------
PART II

               INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

     Chiron Corporation (the "Registrant") files this Registration Statement
with the Securities and Exchange Commission (the "Commission") on Form S-8 to
register 7,200 shares of Chiron Common Stock authorized for issuance pursuant
to outstanding rights under the Viagene, Inc. Employee Stock Purchase Plan,
assumed by the Registrant at the effective time of the merger of Viagene, Inc.
with and into a wholly-owned subsidiary of the Registrant, following which
Viagene, Inc. became a wholly-owned subsidiary of the Registrant.

ITEM 3.  INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE.

     The Registrant hereby incorporates by reference into this Registration
Statement the following documents previously filed with the Commission:

     (a)  The Registrant's Annual Report on Form 10-K for the year ended
December 31, 1994 filed pursuant to Section 13(a) of the Securities Exchange Act
of 1934 (the "1934 Act");

     (b)  Amendment Number 1 to Registrant's Annual Report on Form 10-K for the
year ended December 31, 1994, dated April 24, 1995;

     (c)  Amendment Number 2 to the Registrant's Annual Report on Form 10-K for
the year ended December 31, 1994, dated December 11, 1995;

     (d)  The Registrant's Quarterly Report on Form 10-Q for the quarter ended
April 2, 1995 filed pursuant to Section 13 of the 1934 Act;

     (e)  Amendment Number 1 to Registrant's Quarterly Report on Form 10-Q for
the quarter ended April 2, 1995, dated July 28, 1995;

     (f)  The Registrant's Quarterly Report on Form 10-Q for the quarter ended
July 2, 1995 filed pursuant to Section 13 of the 1934 Act;

     (g)  The Registrant's Quarterly Report on Form 10-Q for the quarter ended
October 2, 1995 filed pursuant to Section 13 of the 1934 Act;

     (h)  The Registrant's Current Reports on Form 8-K and 8-K/A dated January
4, 1995 as amended on March 17, 1995;

     (i)  The Registrant's Current Report on Form 8-K dated March 6, 1995;

     (j)  The Registrant's Current Report on Form 8-K dated March 10, 1995;

     (k)  The Registrant's Current Report on Form 8-K dated April 24, 1995;

                                      II-1
(l)  The Registrant's Current Report on Form 8-K dated May 5, 1995;

     (m)  The Registrant's Current Report on Form 8-K and 8-K/A dated September
29, 1995, as amended on November 13, 1995; and

     (n)  The description of Registrant's Common Stock contained in its
Registration Statement on Form 8-A filed with the Commission on August 28, 1984.

     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 filing of such documents.

ITEM 4.  DESCRIPTION OF SECURITIES.

     Not applicable.

ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.

     William G. Green, who has provided an opinion to the Registrant on the
validity of the securities being registered which is Exhibit 5 to this
registration statement, is Senior Vice President, General Counsel and Secretary
of the Registrant.

ITEM 6.  INDEMNIFICATION OF DIRECTORS AND OFFICERS.

     Section 145 of the General Corporation Law of the State of Delaware and the
Bylaws of the Registrant contain provisions covering indemnification of
corporate directors, officers and employees under certain conditions and subject
to certain limitations.

     In addition, the Registrant has entered into supplemental indemnification
agreements with its directors which broaden the scope of indemnity beyond that
expressly provided by the Bylaws or the Delaware General Corporation Law.  These
supplemental contracts are permissible under the Delaware General Corporation
Law and have been approved by the Registrant's stockholders.  Accordingly, the
indemnification agreements with directors (i) confirm the present indemnity
provided to them by the Registrant's Bylaws and give them assurance that this
indemnity will continue to be provided despite future changes in the Bylaws, and
(ii) provide that, in addition, the directors shall be indemnified to the
fullest possible extent permitted by law against all expenses (including
attorneys' fees), judgments, fines and settlement amounts, incurred or paid by
them in any action or proceeding, including any action by or in the right of the
Registrant, on

                                      II-2
account of their service as a director or officer of the Registrant, or as a
director or officer of any subsidiary of the Registrant, or as a director,
officer or similar official of any other company or enterprise when they are
serving in such capacities at the request of the Registrant.  The
indemnification agreements further provide that expenses incurred by a director
in such cases shall be paid in advance, subject to the director's obligation to
reimburse the Registrant in the event it ultimately determines that the director
is not entitled to be indemnified for such expenses under any of the provisions
of the indemnification agreement.  However, no indemnity will be provided to any
director under the agreements as described in clause (ii) of the third sentence
of this paragraph on account of conduct which is finally adjudged to be
knowingly fraudulent, deliberately dishonest or to constitute willful
misconduct.  In addition, no indemnification will be provided if a final court
adjudication shall determine that such indemnification is not lawful, or in
respect to any suit in which judgment is rendered against a director for an
accounting of profits made from a purchase or sale of securities of the
Registrant in violation of Section 16(b) of the 1934 Act, as amended, or of any
similar statutory provision, or on account of any remuneration paid to a
director which is finally adjudged to have been paid in violation of law.  The
indemnification agreements also contain provisions designed to protect the
Registrant from unreasonable settlements or redundant legal expenditures.

     The Registrant maintains liability insurance for each of its directors and
officers which provides for coverage for certain liabilities for which
indemnification by the Registrant may not be permissible under applicable law
and public policy, including liabilities under the Securities Act of 1933, as
amended.

ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.

     Not applicable.

ITEM 8.  EXHIBITS.

EXHIBIT NUMBER      EXHIBIT
- --------------      -------

          4.01      Rights Agreement, dated as of August 25, 1994, between the
                    Company and Continental Stock Transfer & Trust Company,
                    which includes the Certificate of Designations for the
                    Series A Junior Participating Preferred Stock as Exhibit A,
                    the form of Right Certificate as Exhibit B and the Summary
                    of Rights to Purchase Preferred Shares as Exhibit C,
                    incorporated by reference to Exhibit 4.04 of the
                    Registrant's current report on Form 8-K dated August 25,
                    1994.

          4.02      Amendment No. 1 to Rights Agreement dated as of November 20,
                    1994, between Chiron Corporation and Continental Stock
                    Transfer &

                                      II-3
Trust Company, incorporated by reference to Exhibit 4.05 of
                    the Registrant's current report on Form 8-K, dated November
                    20, 1994.

          5         Opinion of William G. Green.
          23.1      Consent of KPMG Peat Marwick LLP, Independent Auditors,
                    relating to the 1994 consolidated financial statements of
                    Chiron Corporation and subsidiaries.
          23.2      Consent of Ernst & Young LLP, Independent Auditors, relating
                    to the 1993 and 1992 consolidated financial statements of
                    Chiron Corporation.
          23.3      Consent of Ernst & Young LLP, Independent Auditors, relating
                    to the consolidated financial statements of Ciba Corning
                    Diagnostics Corp.
          23.4      Consent of KPMG Peat Marwick LLP, Independent Auditors,
                    relating to the financial statements of The Biocine Company.
          23.5      Consent of Reconta Ernst & Young, Independent Auditors,
                    relating to the consolidated financial statements of JV Vax
                    B.V.
          23.6      Consent of Ernst & Young LLP, Independent Auditors,
                    relating to the financial statements of Viagene, Inc.
          23.7      Consent of William G. Green is contained in Exhibit 5.
          24        Power of Attorney.  Reference is made to pages II-6 and II-7
                    of this Registration Statement.
          99.1      Viagene, Inc. Employee Stock Purchase Plan.

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 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, and (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 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 the registration statement; and (2) that for the
purpose of determining any liability under the Securities Act of 1933 each such
post-effective amendment shall 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; (3)
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.

     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

                                      II-4
reference into the Registration Statement shall 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 foregoing provisions, or otherwise,
the Registrant has been informed that in the opinion of the Securities and
Exchange 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.

                                      II-5
SIGNATURES

     Pursuant to the requirements of the Securities Act of 1933, the Registrant
certifies that it has reasonable grounds to believe that it meets all of the
requirements for filing on Form S-8 and has duly caused this Registration
Statement to be signed on its behalf by the undersigned, thereunto duly
authorized in the City of Emeryville, State of California, on the 19th day of
December, 1995.

                                   CHIRON CORPORATION

                                   By /s/ Edward E. Penhoet
                                      ----------------------------------
                                      Edward E. Penhoet
                                      President and Chief Executive Officer

                                POWER OF ATTORNEY

     KNOW ALL PERSONS BY THESE PRESENTS, that the undersigned officers and
directors of Chiron Corporation, a Delaware corporation, do hereby constitute
and appoint Edward E. Penhoet and William J. Rutter, and each of them, the
lawful attorneys and agents or attorney and agent with full power and authority
to do any and all acts and things and to execute any and all instruments which
said attorneys and agents, and any one of them, determine may be necessary or
advisable or required to enable said corporation to comply with the Securities
Act of 1933, as amended, and any rules or regulations or requirements of the
Securities and Exchange Commission in connection with this Registration
Statement.  Without limiting the generality of the foregoing power and
authority, the powers granted include the power and authority to sign the names
of the undersigned officers and directors in the capacities indicated below this
Registration Statement, to any and all amendments, both pre-effective and post-
effective, and supplements to this Registration Statement, and to any and all
instruments or documents filed as part of or in conjunction with this
Registration Statement or amendments or supplements thereof, and each of the
undersigned hereby ratifies and confirms all that said attorneys and agents, or
any one of them shall do or cause to be done by virtue hereof.  This Power of
Attorney may be signed in several counterparts.

     IN WITNESS WHEREOF, each of the undersigned has executed this Power of
Attorney as of the date indicated.

                                      II-6
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.
SIGNATURE                            TITLE                            DATE
/s/ Edward E. Penhoet, Ph.D.         President, Chief Executive       December 19, 1995
- --------------------------------     Officer and Director (Principal
(Edward E. Penhoet, Ph.D.)           Executive Officer)

/s/ William J. Rutter, Ph.D.         Chairman of the Board            December 19, 1995
- --------------------------------
(William J. Rutter, Ph.D.)

/s/ Dennis L. Winger                 Senior Vice President, Finance   December 19, 1995
- --------------------------------     and Administration, Chief
(Dennis L. Winger)                   Financial Officer (Principal
                                     Financial and Accounting
                                     Officer)

/s/ Gilbert F. Amelio, Ph.D.         Director                         December 19, 1995
- --------------------------------
(Gilbert F. Amelio, Ph.D.)

/s/ Lewis W. Coleman                 Director
- --------------------------------
(Lewis W. Coleman)

/s/ Pierre E. Douaze                 Director                         December 19, 1995
- --------------------------------
(Pierre E. Douaze)

/s/ Donald A. Glaser, Ph.D.          Director                         December 19, 1995
- --------------------------------
(Donald A. Glaser, Ph.D.)

/s/ Alex Krauer, Ph.D.               Director                         December 19, 1995
- --------------------------------
(Alex Krauer, Ph.D.)

/s/ Francois L'Eplattenier, Ph.D     Director                         December 19, 1995
- --------------------------------
(Francois L'Eplattenier, Ph.D.)

/s/ Henri Schramek, Ph.D.            Director                         December 19, 1995
- --------------------------------
(Henri Schramek, Ph.D.)

/s/ Jack W. Schuler                  Director                         December 19, 1995
- --------------------------------
(Jack W. Schuler)

/s/ Pieter J. Strijkert, Ph.D.       Director                         December 19, 1995
- --------------------------------
(Pieter J. Strijkert, Ph.D.)
II-7
SECURITIES AND EXCHANGE COMMISSION
                             WASHINGTON, D.C.  20549

                                    EXHIBITS
                                       TO
                                    FORM S-8
                                      UNDER
                             SECURITIES ACT OF 1933

                               CHIRON CORPORATION
EXHIBIT INDEX

EXHIBIT NUMBER      EXHIBIT
- --------------      -------

          4.01      Rights Agreement, dated as of August 25, 1994, between the
                    Company and Continental Stock Transfer & Trust Company,
                    which includes the Certificate of Designations for the
                    Series A Junior Participating Preferred Stock as Exhibit A,
                    the form of Right Certificate as Exhibit B and the Summary
                    of Rights to Purchase Preferred Shares as Exhibit C,
                    incorporated by reference to Exhibit 4.04 of the
                    Registrant's current report on Form 8-K dated August 25,
                    1994.

          4.02      Amendment No. 1 to Rights Agreement dated as of November 20,
                    1994, between Chiron Corporation and Continental Stock
                    Transfer & Trust Company, incorporated by reference to
                    Exhibit 4.05 of the Registrant's current report on Form 8-K,
                    dated November 20, 1994.

          5         Opinion of William G. Green.
          23.1      Consent of KPMG Peat Marwick LLP, Independent Auditors,
                    relating to the 1994 consolidated financial statements of
                    Chiron Corporation and subsidiaries.
          23.2      Consent of Ernst & Young LLP, Independent Auditors, relating
                    to the 1993 and 1992 consolidated financial statements of
                    Chiron Corporation.
          23.3      Consent of Ernst & Young LLP, Independent Auditors, relating
                    to the consolidated financial statements of Ciba Corning
                    Diagnostics Corp.
          23.4      Consent of KPMG Peat Marwick LLP, Independent Auditors,
                    relating to the financial statements of The Biocine Company.
          23.5      Consent of Reconta Ernst & Young, Independent Auditors,
                    relating to the consolidated financial statements of JV Vax
                    B.V.
          23.6      Consent of Ernst & Young LLP, Independent Auditors,
                    relating to the financial statements of Viagene, Inc.
          23.7      Consent of William G. Green is contained in Exhibit 5.
          24        Power of Attorney.  Reference is made to pages II-6 and II-7
                    of this Registration Statement.
          99.1      Viagene, Inc. Employee Stock Purchase Plan.