Nearly half of all external grants from the US National Institutes of Health require approval by the recipient organization's Institutional Animal Care and Use Committee (IACUC) before the funds can be used for research with animals. Given that large sums of money are spent annually on research involving animals, studies evaluating the strengths, weaknesses and overall effectiveness of IACUCs and similar animal welfare committees are needed. The authors designed and carried out a self-assessment survey on IACUC function and effectiveness. They found that 98% of all respondents believed that their IACUCs advanced animal welfare, but in many instances, veterinarians' responses to individual survey items were significantly different from those of other IACUC members. Protocol compliance, protocol review training and better understanding among non-committee members of the need for regulatory oversight are some areas where improvements could be made. Less than 50% of respondents stated that literature searches to find alternatives to animal use or painful or distressful procedures were helpful.