ERCP [endoscopic retrograde cholangiopancreatography] was evaluated on the basis of 805 examinations. Visualization of the common bile duct and the pancreatic duct was possible in 44%, of the common bile duct in 22% and of the pancreatic duct alone in 24.6% of the cases. The ductal systems were not opacified in 9.4% but the failure rate decreased from 18.2% and 5.4%. Pathological changes were found in both ducts in 2%, in the common bile duct in 42.2% and the pancreatic duct in 11.4% of the cases. Diagnostic information was supplied by ERCP in 84.4% of the cases. Complications developed in 4 cases (acute pancreatitis in 3 and cholangitis in 1). There was no mortality in the entire series. ERCP is a valuable diagnostic method that is frequently successful and reasonably safe.