Objective: To elucidate the prognostic prediction superiority of the tumor size (Ts) in gastric cancer (GC) patients, compared to the depth of tumor invasion (T stage).Methods: Clinicopathological data of 1521 GC patients who underwent the curative resection between 1997 and 2006 were statistically analyzed for demonstration the prognostic significances of Ts, and T stage.Besides, Tumor size-Node-Metastasis (TsNM) classification system was also evaluated the comparative superiorities of the prognostic prediction of GC patients, compared to the seventh edition TNM classification system.Results: With the univariate and multivariate analyses, Ts was identified as the independently prognostic predictor of GC patients, as was T stage.Ts was demonstrated to have the smaller Akaike information criterion (AIC) and Bayesian Information Criterion (BIC) values within the Cox regression analyses than T stage, which represented the optimum prognostic stratification.Not second to TNM classification, TsNM classification was also identified to be competent for accurately prognostic evaluation of GC patients.The case-control matched logistic regression showed that TsNM classification could provide much powerful discriminations of patients overall survival (OS), compared to TNM classification.Additionally, Ts stage was identified to be used to enhance the survival discriminations in patients with given clinicopathological characteristics, including male, T4a stage, N0 stage, diffuse type of Lauren classification, or age ≤ 60 years old.Conclusion: Ts should be recommended as an important clinicopathologic variable for enhancement the accuracy of the prognostic prediction of GC patients in clinic.