Purpose: Palliative gastrectomy and chemotherapy are important options for peritoneal seeding of gastric cancer. The treatment stage IV gastric cancer patient who respond to induction chemotherapy, is converted to gastrectomy (conversion therapy or conversion surgery). This study explored the clinical outcomes of gastric cancer patients with peritoneal seeding who had undergone conversion therapy. Materials and Methods: Between 2003 and 2012, gastric cancer patients with peritoneal seeding, as determined by preoperative or intraoperative diagnosis were reviewed retrospectively. Clinicopathologic characteristics and clinical outcomes of patients with peritoneal seeding were analyzed. Results: Forty-three patients were enrolled. Eighteen patients had undergone conversion surgery and 25 patients continued conventional chemotherapy. Among the 18 conversion patients, 10 received clinically curative resection. The median follow-up period was 28.5 months (range 8 to 60 months) and the total 3-year survival rate was 16.3%. The median survival time of the patients who received clinically curative conversion therapy was 37 months, and the 3-year survival rate was 50%. The median follow-up for non-curative gastrectomy patients was 18 months. No patient treated using chemotherapy survived to 3 years; the median survival time was 8 months. The differences in survival time between the groups was statistically significant (P<0.001). Conclusions: In terms of survival benefits for gastric cancer patients with peritoneal seeding, clinically curative conversion therapy resulted in better clinical outcomes.