A 61-year-old male complained of easy fatigue. Gastroscopy revealed a gastric carcinoma. CT showed No.3 and No.7 lymph nodes swelling. Distant metastasis was not found. S-1 (120 mg/day) was administered for 28 days followed by 14- day rest as one course. Total gastrectomy was performed for 2 weeks after the chemotherapy. Pathology revealed no cancer cells in the gastric wall and dissected lymph nodes. The pathological effect was judged as Grade 3. This case suggests that S-1 therapy may be useful for elderly patients and patients with poor renal function.