Purpose: There is no established treatment-related prognostic factor for gastric cancer except a curative tumor resection. This study was done to clarify the prognostic value of early postoperative intraperitoneal chemotherapy (EPIC) in patients with serosa-positive gastric cancer. Materials and Methods: We analyzed retrospectively the postoperative survival data of 209 patients with serosapositive gastric cancer treated by surgery and chemotherapy. The survival period for patients was calculated from the date of resection until cancer-related death or the last date of follow-up; Kaplan-Meier survival curves were plotted and compared by using the log-rank test. A multivariate analysis was done by using the Cox proportional hazards model. Results: Statistically significant differences in survival rates were noted based on gender, depth of invasion, lymph node metastasis, distant metastasis, stage, location of tumor, macroscopic type, extent of gastric resection, curability of surgery, and adjuvant chemotherapy. Five-year survival rates of patients who received EPIC and systemic chemotherapy were 49 per cent and 25 per cent, respectively (P=0.009). A multivariate analysis revealed that invasion of an adjacent organ, lymph node metastasis, total gastrectomy, and palliative surgery were poor independent prognostic factors. Also, EPIC had a marginal prognostic value (P=0.056). Conclusion: Perioperative intraperitoneal chemotherapy can possibly be one of the independent prognostic indicators in case of serosa-positive gastric cancer