We report a case of “Dieulafoy's ulcer” in the ileum presented with massive hemorrhage. A 56-year-old man who had been treated for acute lymphocytic lymphoma suddenly had massive anal bleeding and was admitted to the hospital. The site of bleeding was determined mid-ascending colon by an emergency selective superior angiography at first time, but obvious bleeding point was not identified. So an ascending colostomy was undertaken. Four days later, massive bleeding occurred from the oral side of the colostomy of the ascending colon. Emergency selective angiography showed extravasation of contrast medium in the ileum. A catheter was induced into the mesenteric artery supplying the lesion, and the patient was transferred to the operating room immediately. Dye solution was injected intraoperatively, and a blue-stained segment of the ileum was resected. Histologic examination showed an ileal mucosal ulcer with ruptured arteries in the submucosal layer, compatible with Dieulafoy's ulcer. Such lesion has been called by many terms, including “cirsoid aneurysm”, and these terms are meant the same disease.