These positions are meant to provide a system of checks and balances which is not normally achieved if any one person fills more than one of these roles. While the regulations do not specifically prohibit one person from filling more than one role, the Animal and Plant Health Inspection Service (APHIS) strongly discourages such assignments because of the potential for conflicts of interest and/or undue influence by one person over the facility’s program. However, a veterinarian who is not the attending veterinarian may assume any one of the other program positions.

The Institutional Official (IO) at a research facility is the person authorized to legally commit on behalf of the facility that the requirements of the regulations will be met. The IACUC reports its inspection findings and recommendations to the IO to ensure the IO is aware of deficiencies at the facility and commits facility resources to making corrections. The IO should therefore be someone with the authority to promulgate, implement, and enforce policies across departmental lines. The IO should also have the fiscal authority to provide for adequate staffing, program improvements, facility repairs, and renovations that meet the needs of the institution’s program.

The Institutional Animal Care and Use Committee shall be composed of a Chairman and at least two additional members, for a total minimum of at least three persons.

For Animal Welfare Act (AWA) enforcement purposes, the nonaffiliated member of the Institutional Animal Care and Use Committee (IACUC) is to "provide representation for general community interests in the proper care and treatment of animals." The person filling this position is intended to represent society’s "less specialized" nonscientific concerns regarding the welfare of the animal subjects. APHIS has determined the nonaffiliated member should not be a laboratory animal user at any research facility.

Compensation of the nonaffiliated member is permissible only when it does not jeopardize the member’s status as a nonaffiliated member. Compensation varies but is normally limited to payment for travel and related expenses, such as parking and meals, to modest monetary payments for participation. The dollar amount of compensation, if any, should not be so substantial as to be considered an important source of income or to influence voting on the IACUC.

IACUC members must be qualified to assess the research facility’s animal program, facilities and procedures. The research facility is responsible for ensuring their qualification, and this responsibility is filled in part through the provision of training and instruction. For example, IACUC members should be trained in understanding the Animal Welfare Act, protocol review, and facility inspections.

No IACUC member can review his/her own proposal.