The Institute of Laboratory Animal Resources of the National Research Council, National Academy of Sciences proposes to develop guidelines for the recognition and alleviation of pain and distress in laboratory animals. The program goal is to assist institutions, scientists, and animal-care personnel in accomplishing their research objectives, while meeting their legal obligations under the amendments to the Animal Welfare Act (7 U.S.C. 2143) and portions of the Health Research Extension Act of 1985 (42 U.S.C. 289d). To conduct the proposed project, ILAR will establish an eight-member committee, comprised of recognized biomedical investigators and experts in laboratory animal science and medicine. The guidelines are expected to address definitions of pain, distress, anxiety, discomfort, and suffering in animals; clinical signs; assessment of clinical signs; and nonpharmacologic and pharmacologic methods of alleviating pain. It is anticipated that the report, which will require 18- months to complete, will be in the form of a handbook to provide a ready source of information for laboratory animal veterinarians; animal caretakers; and scientists, laboratory technicians, and students who work with experimental animals.