Individuals who are seropositive for the human immunodeficiency virus (HIV) frequently have disorders affecting the anorectum, yet little has been reported on this subject. We reviewed our initial experience with patients with HIV referred to the Division of Colon and Rectal Surgery. Forty patients (age range, 19-45 years; mean, 32.2 years) were seen between 1985 and 1989. The mean duration of symptoms was six months (range, one week to six years). In 25 patients (63 percent), more than one anorectal condition was identified. Condylomata were seen in 21 patients (52 percent), and in 11 these were associated with other pathologies. Fistulas and/or abscesses were identified in 15 patients (37 percent). Three had a "watering-can perineum," all without any identifiable predisposing factors. Nineteen patients had symptomatic hemorrhoids (seven), fissures (17), and/or perianal herpes infections (five), usually in combination with other lesions (89 percent). Three individuals developed neoplastic processes. Rectal disease was discovered in addition in nine patients. This included nonspecific proctitis in four, a rectal mass in four (polyps, two; rectal diverticulum, one; and Kaposi's sarcoma, one), and a nonspecific rectal ulcer in one. Four patients had other symptoms, including diarrhea, incontinence, soiling, frequency, and/or urgency, always in combination with other anal disorders. Seventy-one operative procedures were performed in 31 patients (78 percent). Only six (8 percent) of these were for diagnosis and biopsy alone. Mean follow-up was 15.5 months in the 23 patients followed for greater than one month. Only 6 of 23 (26 percent) had resolution of their problem. Nine (39 percent) developed new perianal conditions. Anorectal disorders are often seen in patients infected with HIV. They may be aggressive, cause significant morbidity, and be difficult to resolve.