Massive haemorrhage due to rupture of single pancreatic or peripancreatic vessels is a very rare but potentially lethal complication of acute and chronic pancreatitis. The splenic, gastroduodenal, and pancreatoduodenal arteries are the more commonly involved vessels, and rupture occurs mostly as a complication of large mature pseudocysts. We report a sudden death due to massive bleeding caused by rupture of the great pancreatic artery (arteria pancreatica magna), a complication of a small immature pseudocyst, in a 49-year-old male alcoholic with inactive chronic pancreatitis.