Twenty-one major abdominal operations performed on 20 patients with Acquired Immunodeficiency Syndrome (AIDS) were reviewed. Fourteen operations were for therapeutic indications, eight were emergent. The array of pathology encountered included opportunistic infection with Mycobacterium avium intracellulare, Cytomegalovirus, Cryptosporidium, abdominal tuberculosis, lymphoma, Kaposi's sarcoma, AIDS-related immune thrombocytopenia, perforated appendicitis and colonic pseudo-obstruction. Hospital mortality was 20 per cent. Major morbidity occurred in 15 per cent of patients and was more common following emergency operations. Preoperative demographic, hematologic, or nutritional parameters examined or the presence of single-organ system dysfunction did not predict outcome. Fifty-three per cent of hospital survivors are alive with a nine-month median postoperative follow-up. It is concluded that major abdominal procedures in patients with AIDS should not be withheld due to fear of excessive morbidity or mortality. General surgeons are involved in the evaluation and treatment of increasing numbers of patients with HIV infection. Appropriate management requires recognition of a wide range of surgical pathology and attention to details of safe intraoperative conduct.