Hemorrhage into a pancreatic pseudocyst is a rare, but increasingly recognized as a cause of massive gastrointestial bleeding. Bleeding pseudocysts may rupture into the stomach, duodenum, common bile duct, and splenic vein, or can be decompressed via the duct of Wirsung. Also it will result in upper gastrointestinal bleeding. This represents a life-threatening and frequently unrecognized complication of pancreatic disease. Proper diagnostic workup and prompt surgical management afford the patient the best chance for survival . We report a patient with pseudocyst bleeding into the gastrointestinal tract via the duct of Wirsung and discuss the current diagnostic and therapeutic approach. (Kor J Gastrointest Endosc 15: 803-807, 1995)