An umbilical metastasis of gastric cancer is known as Sister Mary Joseph's nodule. It ordinarily indicates a poor prognosis because umbilical metastasis often develops with peritoneal dissemination. Herein, we report a case of umbilical metastasis of gastric cancer that showed good response to chemotherapy, including the oral anticancer agent TS-1. The patient was a 55-year-old man in which gastric cancer was found by upper gastrointestinal series. Physical examination revealed an umbilical nodule that had an irregular surface and a hard consistency. Ultrasonography showed a 15 x 10 mm hypoechoic mass under the umbilicus. Core needle biopsy of the umbilical mass revealed adenocarcinoma. Peritoneal dissemination was proved by diagnostic laparoscopy. Oral anticancer agent TS-1 was administered with low-dose cis-platinum. The gastric lesion and umbilical nodule showed marked response to the chemotherapy and the response continued for 20 months. The patient died of disease progression 31 months after the initiation of the treatment.