We treated a woman with simultaneous adenocarcinoma of the stomach and fourth portion of the duodenum. She complained of symptoms of obstruction in the duodenum, and both lesions were correctly diagnosed, preoperatively. Noncurative resection was done because of distant lymph node metastasis. The new adjuvant chemotherapy using THP-adriamycin and UFT was prescribed, and one year after surgery she remains in recession.