2004 Committee Charter : SIAL

The Board of Directors of Sigma-Aldrich Corporation (the "Company") hereby adopts this Charter to govern the composition of its Corporate Governance Committee (the "Committee") and the scope of the Committee's duties and responsibilities, and to set forth specific actions the Board of Directors expects the Committee to undertake to fulfill those duties and responsibilities.

I. STATEMENT OF PURPOSE

The Committee will consider and make recommendations to the Board concerning the qualification and compensation of members of the Board and its committees, as well as the size and composition of the Board and its committees, and will consider and approve nomination of candidates for election to the Board. The Committee will also periodically review the Corporate Governance Guidelines and the Business Conduct Policy adopted by the Board and make such recommendations to the Board as the Committee deems appropriate concerning any changes in such Guidelines and Code and the Board's and the Company's operations as provided therein.

II. COMPOSITION OF THE CORPORATE GOVERNANCE COMMITTEE

The Committee shall be comprised of at least three members of the Board of Directors, with the number of members to be determined from time to time by the Board. The members shall be designated by the Board of Directors. All of the members shall be independent directors.

III. MEETINGS

The Committee shall meet at least once annually, or more frequently as the Committee may from time to time determine to be appropriate. Unless the Board has previously designated a Chair, the members of the Committee may designate a Chair by majority vote. A majority of the Committee members shall constitute a quorum.

Teleconferences may also be held at such other times as shall be reasonably requested by the Chairman of the Board or the Chair of the Committee.

The Chair shall prepare the agenda for Committee meetings, after consultation with the Chairman of the Board and Chief Executive Officer and subject to the right of the Committee members to suggest additional items for the agenda. Agendas are shared with Committee members in advance of meetings. As a general rule, subject to appropriate procedures to protect the confidentiality of particularly sensitive information, appropriate background and explanatory materials concerning matters to be discussed at Committee meetings shall be sent to Committee members in advance.

Committee meetings will normally be attended by the Chairman of the Board, unless the matter or matters to be discussed at the meeting would make it appropriate to excuse him/her. At the invitation of the Chair, meetings may also be attended by other members of management and other persons as are appropriate to matters under consideration.

The Committee and its members have complete access to management, recognizing that it is expected that members will use judgment to be sure that this access is not distracting to the business operations of the Company. The Committee may engage the services of outside advisors if it shall determine such services to be necessary or appropriate for the proper discharge of its duties. Should any member of the Committee believe that participation of management or outside advisors in discussion of a particular subject would be advisable, they are encouraged to make that request.

The Chair will present an oral report of Committee meetings and other proceedings at each Board meeting. Proposals which require Board action will normally be submitted by the Committee to the Board in writing.

IV. DUTIES AND RESPONSIBILITIES OF THE CORPORATE GOVERNANCE COMMITTEE

The duties and responsibilities of the Committee shall include the following:

A. Size and Composition of Board. Review, at least annually, the size, structure and membership of the Board and its committees to assure that the proper skills and experience are represented on the Board and its committees. In conducting its review, the Committee shall consider the contributions of existing Directors and the overall needs of the Company.

B. Potential Candidates. Maintain a list of persons who may be potential Directors, seek out possible candidates and otherwise aid in attracting highly qualified candidates as Directors.

C. Approve Nominees. Evaluate and approve nominees for election to the Board, after consultation with the Chairman of the Board and the Chief Executive Officer, as well as other members of the Board. The Committee shall consider the knowledge, experience, integrity and judgment of possible candidates for nomination as a Director; their potential contribution to the diversity of backgrounds, experience and competencies which the Board desires to have represented; and their ability to devote sufficient time and effort to their duties as Directors. Following approval by the full Board, invitations to join the Board are extended by the Chairman of the Board.

Consider nominees recommended by shareholders for election to the Board provided the names of such nominees, accompanied by relevant biographical information, are submitted in writing to the Secretary of the Company on a timely basis.

Consider and recommend to the Board the position to be taken with respect to any persons nominated by shareholders for election to the Board in accordance with the Company's By-Laws.

D. Board Vacancies. Nominate for Board approval persons to fill vacancies on the Board.

It is the sense of the Board that individual Directors who change the responsibility they held when they were elected to the Board should submit his/her resignation to the Board. It is not the sense of the Board that in every instance such Directors should necessarily leave the Board. The Committee shall, however, assess whether or not it is appropriate for such a Director to continue to serve on the Board.

E. Board Compensation. Review, annually, the status of Director compensation in relation to other similarly situated companies and make recommendations to the Board with respect to changes in Director compensation.

F. Composition of Committees. Make recommendations with respect to committee duties and, after consultation with the Chairman of the Board and Chief Executive Officer and consideration of the background of individual Board members, recommend annually to the Board the assignment of members to committees and the designation of committee chairs. The Committee shall consider periodic rotation of committee members, particularly committee chairs; however, the Committee is not required to recommend rotation of committee members on a specified timetable.

G. Corporate Governance. From time to time, review the Corporate Governance Guidelines adopted by the Board and the Board's operations as provided for therein, and determine whether to recommend any changes to the Board.

H. Business Conduct Policies. From time to time, review the Business Conduct Policies adopted by the Board and the Company's operations as provided for therein, and determine whether to recommend any changes to the Board.

I. Committee Performance. Review, annually, the Committee's performance and determine whether improvements can be made.

J. General. Be available to the Chairman of the Board and other Directors for consultation concerning corporate governance and candidates as Directors and perform such other functions which from time to time may be assigned by the Board.