The majority of cases of duodenal intramural hematoma occur in children due to blunt abdominal trauma. In adult patients, the etiology of hematoma is quite varied. A hematoma may occur due to the usage of anticoagulants, hemophilia, Henoch-Schonlein purpura, vasculitis, pancreatic disease, endoscopic coagulation of duodenal ulcer bleeding and following an endoscopic retrograde cholangiopancreatogram. A 53-year-old male patient was admitted for hematemesis. The patient was a heavy alcoholic and had a history of chronic pancreatitis, but there was no definite trauma history or other medical illness. In the duodenal second portion, a huge submucosal mass obstructed the lumen with submucosal hemorrhage. As depicted on an abdominal CT and an endoscopic ultrasonogram, chronic pancreatitis and a duodenal submucosal tumor was suspected. On the eighth hospital day, abdominal pain suddenly became worse and peritoneal-irritation signs were observed. Therefore, a surgical procedure was urgently performed. Considering the rarity of its etiology in Korea, we report a case of duodenal intramural hematoma complicated with chronic pancreatitis. (Korean J Gastrointest Endosc 2008;37:207-211)