Twenty-nine patients with primary sclerosing cholangitis were reviewed. Males predominated (2:1). Seventy-six per cent presented with cholestasis and cholangitis, 17% with cirrhosis and portal hypertension, and 7% were asymptomatic, presenting with a raised serum alkaline phosphatase. The serum immunoglobulin IgM concentration was raised in 45% of the patients, but no patient had serum mitochondrial antibody present. Seventy-two per cent had ulcerative proctocolitis. There was no relationship between either duration or severity of ulcerative proctocolitis and the development of primary sclerosing cholangitis. Four patients were not benefited by colectomy. None of the patients ahd Crohn's disease. The prognosis was variable. Corticosteriods and azathioprine were ineffective. Eleven patients (38%) had died with a mean survival time of seven years from diagnosis. Three patients with ulcerative proctocolitis developed bile duct carcinoma. The cholangiograms and liver biopsies were reported without reference to clinical information together with 41 patients with other biliary diseases. Cholangiography was diagnostic in 18/22 (82%). Hepatic histology was diagnostic in 8/22 (36%). Ten showed features of large bile duct disease and three were misdiagnosed as primary biliary cirrhosis. Reduced numbers of bile ducts, ductular proliferation, portal inflammation, and substantial copper deposition, in combination with piecemeal necrosis, are commonly seen in primary sclerosing cholangitis and indicate the need for cholangiography.