Primary sclerosing cholangitis (PSC) is a chronic, progressive cholestatic liver disease whose aetiopathogenesis is unknown. PSC is frequently associated with inflammatory bowel disease, in particular chronic ulcerative colitis, is most commonly observed in young males and is clinically characterized by fatigue, pruritus and jaundice. The diagnosis is supported by a cholestatic biochemical profile and histological abnormalities, and confirmed by visualization of an abnormal biliary tree. The natural history of the disease is currently being evaluated but is generally recognized to be slowly progressive, leading to complications of chronic cholestasis, portal hypertension and biliary cirrhosis. There is no specific medical treatment, and orthotopic liver transplantation remains the only definitive treatment for patients with end-stage PSC. A more rational approach to medical therapy will ensue upon a better understanding of the aetiopathogenesis of this disease.