Surgical treatments for curatively unresectable gastric cancer include reduction surgery and palliative surgery(palliative gastrectomy and bypass operation). Both palliative gastrectomy and reduction surgery reduce the tumor volume. In this study, the clinical significance of these treatment methods was investigated. The subjects were 58 patients with unresectable gastric cancer for which surgery was performed as the primary treatment. Of these patients, 38 patients underwent reduction surgery and 20 patients underwent palliative surgery. On univariate analysis, age and gender were not significant. Pre-operative performance status(PS) in patients treated with reduction surgery was favorable compared to that in patients receiving palliative surgery(PS 0: 65.8 vs 40.0%, p=0.06). The administration rate of post-operative chemotherapy in patients treated with reduction surgery was higher than that in patients with palliative surgery (92.1 vs 65.0%, p<0.01). The median survival time in patients treated with reduction surgery was 18.2 months, while that in patients with palliative surgery was 11.0 months (p<0.01). These results indicated that reduction surgery was clinically different compared to palliative surgery in terms of the administration rate of post-operative chemotherapy and prognosis.