Objective: To investigate the the correlation between lymphatic vascular invasion (LVI) and prognosis in T3/T4 gastric cancer after D2 resection, and establish an optimal classification of staging system. Methods: From Jan 2000 to Sep 2010, a total of 1, 283 T3/T4 gastric cancer patients undergoing D2 resection were enrolled. Univariate and multivariate analysis were used to investigate the prognostic value of gastric cancer patients. Homogeneity, discriminatory ability, and monotonicity of gradients of hypothetical N stage and UICC N stage were compared using linear trend χ2, likelihood ratio χ2 statistics, and Akaike information criterion (AIC) calculations. Results: Multivariate analysis identified LVI was an independent prognostic factor. The 3.5-year overall survival were worse in patients with LVI than those without LVI (P<0.001). LVI was corporated into N3b stage performed the optimum prognostic stratification, together with better homogeneity, discriminatory ability and monotonicity of gradients. Conclusion: LVI is an independent prognostic factor for T3/ T4 gastric cancer after D2 resection, and may be considered to be incorporated into the UICC N3b stage.