The present patient was a 69-year-old male diagnosed as gastric cancer with peritoneal dissemination by staging laparoscopy. He was treated with chemotherapy using S-1 (120 mg/body/day) and docetaxel (70 mg/body/day 1) administered for 2 weeks, followed by one drug-free week in three-week courses. After 4 courses of treatment, the primary tumor regressed, but only slightly. Because of an adverse event, we continued with a lower dose. After 4 more courses of treatment, the primary tumor and dissemination were undetectable on abdominal CT scan but were endoscopically detected. The patient has been followed on an outpatient basis without surgical treatment for 2 years.