An ectopic opening of the common bile duct into the duodenal bulb is a very rare congenital malformation of the bile duct, which may cause a recurrent duodenal ulcer or biliary diseases including choledocholithiasis or cholangitis. ERCP plays major role in the diagnosis of this biliary malformation. We report a case of an ectopic opening of the common bile duct into the duodenal bulb, which was detected on the upper gastrointestinal series