Primary sclerosing cholangitis (PSC) is a cholestatic liver disease of unknown cause, with genetic predisposition in combination with environmental factors possibly playing a role. The diagnosis is made on the basis of a liver enzyme profile indicating cholestasis and characteristic bile duct abnormalities in cholangiography or the liver biopsy after excluding other causes. Approximately 80% of patients have concurrent inflammatory bowel disease (IBD), specifically ulcerative colitis in most patients. PSC predisposes to hepatobiliary malignancies such as cholangiocarcinoma, gallbladder carcinoma and hepatocellular carcinoma, as well as to colorectal carcinoma in patients with concurrent IBD.- UDCA and endoscopic bile duct dilatation relieve symptoms and improve the liver enzyme profile. Orthotopic liver transplantation is the only potentially curative therapy available.