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:



A1

---



A2

---



QuickLinks