Objective: To investigate the prognostic significance of tumor size in patients with gastric cancer. Methods:To evaluate the influence of tumor size on the outcome, we reviewed 489 gastric cancer patients who underwent surgery and chemotherapy. Results:An appropriate cutoff value of tumor size affecting patient survival was 3 cm. Patients were divided into two groups as follows: small size group (SSG)with tumor size <3 cm, and large size group (LSG) with tumor size ≥3 cm. Tumor size was significantly related to histological grade, status of lymphovascular and vessel invasion, depth of primary tumor invasion, lymph node metastasis and TNM stage. Univariate analysis revealed that the prognosis of patients in SSG was significantly better than that in LSG. Multivariate analysis showed that tumor size was an independent prognostic factor along with macroscopic appearance, depth of primary tumor invasion, lymph node metastasis and distant metastasis. In SSG,patients with T2 and T3 had significant higher 5-year survival rate than those with T2 and T3 in LSG. Conclusion:Tumor size is one of highly significant parameters, served as independent predictor of survival in patients with gastric cancer.