Primary sclerosing cholangitis is a cholestatic liver disease characterized by fibroobliterative inflammation of the entire biliary tree. It is a slowly progressive disease with an undulating course, resulting in biliary cirrhosis. The gold standard for establishing the diagnosis is cholangiographic demonstration of typical diffuse biliary stricturing and beading. We exprienced a case of primary sclerosing cholangitis by Endoscopic retrograde cholangiopancreatography (ERCP) demonstration. ERCP findings revealed multiple luminal narrowing, stricture and beaded dilatation of the intrahepatic duct. We report a case of primary sclerosing cholangitis localizing at intrahepatic bile duct, which is confused with cholangiocarcinoma. (Korean J Gastrointest Endosc 2001; 22:250254)