QuickLinks -- Click here to rapidly navigate through this document

Exhibit 10.511

CHIRON CORPORATION AUDIT COMMITTEE CHARTER

ROLE

        The Audit Committee (the "Committee") of the Board of Directors (the
"Board") of Chiron Corporation ("Chiron") assists the Board in fulfilling its
responsibility for oversight of the quality and integrity of the accounting,
auditing and reporting practices of Chiron and its subsidiaries, and such other
duties as directed by the Board. The Committee's role includes oversight of
Chiron's internal audit function and its business ethics standards and
compliance. The Committee's role also includes a particular focus on the
qualitative aspects of financial reporting to shareholders, and on Chiron's
processes to manage business and financial risk and processes to assure
compliance with significant applicable legal, ethical and regulatory
requirements. The Committee is directly responsible for the appointment,
compensation, retention and oversight of the work of Chiron's independent
auditors, including resolving disagreements between management and the
independent auditors regarding financial reporting.

        Except to the extent otherwise directed by the Board or required by
applicable law or Chiron's Certificate of Incorporation or Bylaws, this
Committee shall have the full authority of the Board over any matter with
respect to which oversight or direction is required to be exercised solely by
directors who satisfy the independence criteria specified in this charter for
membership on this Committee. The chairperson of the Committee, acting in
consultation with all committee members who are not otherwise affected by the
issue or interest under consideration, and in consultation with such other
directors, representatives of management, counsel or other advisors as the
chairperson may deem appropriate, may determine from time to time the scope of
the Committee's authority under this charter.

MEMBERSHIP

        The membership of the Committee shall consist of at least three
directors, each of whom is able to read and understand financial statements,
including a company's balance sheet, income statement and cash flow statement,
and the Committee shall have at least one member that the Board of Directors has
determined is a "financially-sophisticated person" as such term is defined by
the Nasdaq Stock Market, Inc. ("Nasdaq"). A member shall not be an officer or
employee of Chiron, each member shall be free of any relationship that, in the
determination of the Board, would interfere with his or her individual exercise
of independent judgment and each member shall otherwise be "independent" and
qualified to serve as a member of the Committee under applicable law and under
the rules of Nasdaq and the Securities and Exchange Commission (the "SEC"). The
Committee shall review, at least annually, and upon the occurrence of any
significant change, the qualification and independence of its members, and shall
report the result of this review to the full Board. No member of the Audit
Committee shall receive, directly or indirectly, any compensation from Chiron
other than in such member's capacity as a member of the Board or of any
committee of the Board.

        Subject to the requirements described above with respect to Committee
membership, members of the Committee shall be appointed by the Board in
accordance with the Governance Agreement, dated as of November 20, 1994, between
the Company and Novartis AG, as amended (as it may be further amended from time
to time, the "Governance Agreement"). Committee members shall serve at the
pleasure of the Board. The chairperson shall be appointed by the full Board.

        The Committee shall meet in person or telephonically at least four times
a year or more frequently when deemed necessary or desirable by the Committee or
its chairperson, at such times and places as the Committee determines.

1

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

COMMUNICATIONS/REPORTING

        The independent auditors shall report directly to the Committee. The
Committee is expected to maintain free and open communication with the
independent auditors, the internal auditors and Chiron's management. This
communication shall include private executive sessions, at least annually, with
each of these parties. In addition, Chiron's Director of Internal Audit and
Chiron's Chief Compliance Officer shall have direct access to the Committee. The
Committee shall prepare the report required to be prepared by audit committees
for inclusion in Chiron's annual proxy statement. The Committee shall perform or
cause to be performed and approved by the Committee annually an evaluation of
the performance of the Committee of its role under this charter, including the
duties and responsibilities set forth in Annex A. The evaluation shall include
consideration of possible amendments to this charter, including the duties and
responsibilities set forth in Annex A. The performance evaluation may be
conducted in such manner as the Committee deems appropriate, and the result and
recommendations shall be reported to the Board by the chairperson or any other
member of the Committee. The Committee chairperson shall report in a timely
manner on Committee activities to the full Board.

EDUCATION

        Chiron is responsible for providing the Committee with educational
resources related to its role and duties and responsibilities, including audit
committee requirements and practices, accounting principles and procedures,
current accounting topics pertinent to Chiron and any other material as may be
requested by the Committee. Chiron shall assist the Committee in maintaining
appropriate financial literacy.

AUTHORITY

        In discharging its role, duties and responsibilities, the Committee is
empowered to cause and direct the investigation of any matter brought to its
attention, with full power to cause independent counsel or other experts or
advisors to be retained for this purpose. The Committee may require any officer
or employee of Chiron or Chiron's outside lawyers or independent auditors to
attend a meeting of the Committee or to meet with any member of or consultants
to the Committee and to provide any information requested by the Committee or
its member or consultants. The Committee shall have the full authority of the
Board to discharge its duties and responsibilities, including the authority to
select, retain, terminate and approve the compensation and other terms of
engagement of independent counsel, accountants or other experts or advisors as
the Committee deems appropriate in its discretion, without seeking approval of
the Board or management. The Committee shall also have the resources that it
deems necessary to discharge its duties and responsibilities.

        The Committee may, in its discretion, delegate to one or more of its
members the authority to pre-approve any audit or non-audit services to be
performed by the independent auditors, provided that any such approvals are
presented to the Committee at its next scheduled meeting.

KEY DUTIES AND RESPONSIBILTIIES

        The key duties and responsibilities of the Committee in carrying out its
oversight role are delineated in Annex A. Annex A will be reviewed annually, and
updated if necessary, to reflect changes in regulatory requirements,
authoritative guidance and evolving oversight practices. As the compendium of
Committee duties and responsibilities, Annex A will be considered to be
incorporated in, and a part of, this charter.

        The Committee may rely on the expertise and knowledge of management, the
internal auditors, the independent auditors and counsel, advisors and experts in
carrying out its oversight responsibilities. Management of Chiron is responsible
for determining that Chiron's financial statements are complete

2

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

and accurate in accordance with generally accepted accounting principles and
firmly represent the financial condition of Chiron. Management is also
responsible for the effectiveness of disclosure controls and procedures and
internal controls and procedures for financial reporting. The independent
auditors are responsible for auditing Chiron's financial statements. It is not
the duty of the Committee to plan or conduct audits, to determine that the
financial statements are complete and accurate and are in accordance with
generally accepted accounting principles, to conduct investigations, to assure
the adequacy or effectiveness of Chiron's internal controls or disclosure
procedures or to assure compliance with laws and regulations or Chiron's
internal policies, procedures and controls.

3

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

ANNEX A

        The following are the key duties and responsibilities of the Committee:

1.With respect to the independent auditors,

(i)to have direct responsibility for the appointment, compensation (including
the sole authority to approve all audit engagement fees and terms), retention
and oversight of the work of Chiron's independent auditors, including resolution
of disagreements between management and the independent auditors regarding
financial reporting;

(ii)to approve all audit engagement fees and terms, as well as all non-audit
engagements of the independent auditors;

(iii)to pre-approve all audit and non-audit services to be provided by the
independent auditors, and to consider whether its provision of non-audit
services to Chiron is compatible with maintaining the independence of the
independent auditors;

(iv)to review annually the fees billed for each of the last two fiscal years for
the following categories of services rendered by the independent auditors:
(a) the audit of Chiron's annual financial statements and the reviews of the
financial statements included in Chiron's Quarterly Reports on Form 10-Q for
each such fiscal year; (b) assurance and related services that are reasonably
related to the performance of the audit or reviews of Chiron's financial
statements for each such fiscal year, describing each subcategory of services
comprising the fees disclosed under this category; (c) tax compliance, tax
consulting and tax planning services for each such fiscal year; and (d) all
other products or services provided by the independent auditors for each such
fiscal year, describing each subcategory of products or services comprising the
fees disclosed under this category;

(v)to assess the independent auditors' independence by reviewing all
relationships between the independent auditors and Chiron, including each
non-audit service provided to Chiron and the matters set forth in Independence
Standards Board No. 1, and to discuss with the independent auditors any
relationships or services that may impact the quality of audit services or the
objectivity and independence of Chiron's independent auditors;

(vi)to discuss with the independent auditors in connection with any audit of
Chiron's financial statements required under the securities laws, prior to each
filing of the audit report with the SEC, all critical accounting policies and
practices used, all material alternative treatments of financial information
within generally accepted accounting principles that have been discussed with
management, ramifications of the use of such alternative disclosures and
treatments, and the treatment preferred by the independent auditors, and any
material written communications between the independent auditors and management,
such as any "management representation" letter, reports on observations and
recommendations on internal control or schedule of unadjusted differences; and

(vii)to discuss with management the timing and the process for implementing
rotation of any "audit partner" (as defined in the rules of the SEC) in
accordance with the rules of the SEC with respect thereto.

2.With respect to financial reporting principles and policies and internal audit
controls and procedures,

(i)to consider any reports or communications (and management's and/or the
internal audit department's responses thereto) submitted to the Audit Committee
by the independent auditors required by or referred to in SAS 61 (as codified by
AU Section 380), as it may be modified or supplemented;

A1

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

(ii)to establish procedures for the receipt, retention and treatment of
complaints received by Chiron regarding accounting, internal accounting controls
or auditing matters, and for the confidential, anonymous submission by Company
employees of concerns regarding questionable accounting or auditing matters; and

(iii)to establish hiring policies for employees or former employees of the
independent auditors in accordance with applicable law, rules and regulations.

3.With respect to reporting and recommendations,

(i)to review and assess the adequacy of this Charter at least annually; and

(ii)to prepare the report for inclusion in Chiron's annual proxy statement in
accordance with SEC rules, and include a copy of the Committee Charter as an
appendix to the annual proxy statement at least once every three years.

A2

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

QuickLinks

Exhibit 10.511

CHIRON CORPORATION AUDIT COMMITTEE CHARTER ROLE