An anomalous pancreaticobiliary ductal union is a rare anomaly occurring in the biliary tract. This anomaly has been implicated as a cause of choledochal cysts, bile duct and gallbladder carcinoma, and recurrent pancreatitis. A case is herein reported of a 63 year-old woman who suffered from gallbladder cancer associated with a choledochal cyst and an anomalous pancreaticobiliary union. (Korean J Gastrointest Endosc 2000;20:137 140)