Eight homosexual men with the acquired immunodeficiency syndrome (AIDS) presented with clinical, biochemical, and radiologic features of stenosis of the papilla of Vater and sclerosing cholangitis. This newly recognized complication of AIDS produces abdominal pain, nausea, and vomiting and may predispose patients to superimposed bacterial cholangitis. Marked elevation of serum alkaline phosphatase levels and lesser changes in hepatic aminotransferase levels are common. Although abdominal ultrasonography and computed tomography detect ductal abnormalities, endoscopic retrograde cholangiography best shows precise ductal irregularities and provides therapeutic intervention. Prompt relief of symptoms follows endoscopic sphincterotomy, often with resolution of biochemical evidence of cholestasis. Biliary tract infection with cytomegalovirus or cryptosporidia and resultant viral or coccidial cholangitis are the proposed pathophysiologic mechanisms.