We present here in the case of a 75-year-old man who developed synchronous double cancers of the remnant stomach and pancreas 12 years after undergoing distal gastrectomy for gastric carcinoma, The patient was referred to our hospital in March, 1993, with a provisional diagnosis of carcinoma of the remnant stomach. Laboratory data on admission showed an abnormal level of CA19-9 (116.1 U/ml) and positive occult blood in the stools. An upper gastrointestinal series and gastroendoscopy demonstrated an ulcerative polypoid tumor in the gastric stump proximal to the gastroduodenostomy anastomosis, and a biopsy confirmed the findings of mucinous adenocarcinoma. Abdominal computed tomography (CT) scan revealed a low-density nodule anterior to the abdominal aorta, suggestive of a nodal metastasis. A laparotomy was performed which also disclosed a low-density mass located within the head of the pancreas, The patient was subsequently diagnosed as having double carcinomas of the remnant stomach and pancreas, and total gastrectomy and pancreatoduodenectomy were carried out, The histologic sections from the remnant stomach showed mucinous adenocarcinoma, whereas those from the pancreas showed tubular adenocarcinoma. Double carcinomas in this association are extremely rare and this case may in fact be the first observation of synchronous double cancers of the remnant stomach and pancreas.