An intraductal papillary mucinous neoplasm (IPMN) of the pancreas is an uncommon tumor characterized by the production of mucin in the pancreatic duct that occasionally involves the formation of fistulas with surrounding organs, including the stomach, duodenum and common bile duct. The mechanism underlying the formation of such fistulas is direct invasion by a tumor or a combination of high pressure in the main pancreatic duct and inflammatory stimulation. A 73-year-old man was referred to our hospital due to the presence of a gastric ulcer detected on screening gastroscopy. Endoscopic findings showed the presence of a whitish thick mucin coated ulcerative lesion that appeared as a perforation or fistula opening. Abdominal computed tomography and magnetic resonance cholangiopancreatography demonstrated the presence of an IPMN of the pancreas and multiple fistula formation with the neighboring organs. An endoscopic biopsy was carried out to obtain pancreatic tumor tissue through the pancreatogastric fistula and the mass was confirmed as a mucinous adenocarcinoma. To the best of our knowledge, this is the first case of an IPMN associated with a pancreatojejunal fistula and duodenal ulcer bleeding due to fistula formation.