Endoscopic retrograde cholangiopancreatography (ERCP) has proved to be an effective method of evaluation of a wide range of pancreatic and biliary disease.1,2It has advantages over intravenous cholangingraphy in that ERCP can be carried out in patients with advanced hepatic parenchymal disease or high-grade biliary obstruction. Unlike percutaneous cholangiography, the hepatic capsule need not be punctured, thereby obviating the risks of hemorrhage and bile peritonitis. Endoscopic retrograde cholangiopancreatography is uniquely suited to the evaluation of sclerosing cholangitis, which is particularly difficult to evaluate by other than surgical means. Intravenous and oral cholangiography often are not helpful, because there is usually poor biliary opacification in this disease. Percutaneous and transjugular cholangiography usually are not possible if intrahepatic ducts are involved in the diffuse chronic inflammatory process and have narrow lumens that are difficult to enter. Most authors have agreed that the diagnosis can be made only by surgical exploration with