Abstract Twenty-one patients with primary sclerosing cholangitis were seen during 1979–87. The mean age at onset of disease was 51.7 years (range: 13–78 years) with a male: female ratio of 2.5:1. Six (29%) were asymptomatic at the time of diagnosis. Eleven patients (52%) had ulcerative colitis. Cholangiography demonstrated abnormalities limited to the intrahepatic ducts in 10 cases, with both intrahepatic and extrahepatic involvement in 11. Histological features on liver biopsy included: portal tract inflammation and cholestasis in all; paucity of bile ducts in 56%; piecemeal necrosis in 19% and cirrhosis in 6%. Circulating autoantibodies and elevated serum immunoglobulins were found in half of the patients and HLA-B8 was detected in 53%. A deficiency of circulating CD3 and CD8 cells was not found in the 12 patients tested. The mean follow-up was 51 months (range: 3–180 months). Three patients died from non-hepatic causes and another has received liver transplantation. A Kaplan-Meier curve predicted 70% survival at 72 months.