Hemosuccus pancreaticus--blood entering the gastrointestinal tract through the pancreatic duct--is a rare and elusive form of gastrointestinal bleeding. The most common cause is a splenic artery pseudoaneurysm caused by acute or chronic inflammation of the pancreas. We report the case of an 86-year-old woman who had recurrent gastrointestinal bleeding from erosion of an aneurysm of the splenic artery into the pancreatic duct. The lack of associated symptoms, equivocal endoscopic findings, and the rarity of this entity resulted in a delay in diagnosis. Nonresective treatment by ligation of the splenic artery proximal and distal to the aneurysm prevented any additional bleeding. Postoperative technetium sulfur colloid scanning demonstrated normal perfusion of the spleen. Only 16 cases of hemosuccus pancreaticus from primary splenic artery disease have previously been reported in the English-language literature (15 primary aneurysms, one medial disruption without an aneurysm). In contrast to cases caused by inflammatory pseudoaneurysms, splenic artery-pancreatic duct fistulas caused by primary aneurysms of the splenic artery should be treated without pancreatic or splenic resection, either with surgery or by embolization. In elderly patients with recurrent gastrointestinal bleeding of obscure source, the differential diagnosis should include the possibility of a ruptured aneurysm communicating with a viscus.