Objective To investigate the correlation between the prognostic nutritional index (PNI) and clinicopathological features and long-term prognosis of gastric cancer patients after radical gastrectomy.Methods The clinical data of 135 gastric cancer patients who underwent radical gastrectomy in this hospital from 2002 to 2006 was analyzed retrospectively.The PNI value was calculated by serum albumin (g/L) + 5 x lymphocyte count (× 109/L).The receiver operating characteristic (ROC) curve and Youden index was used to determine the cutoff value of the PNI.Survival curves were described by the Kaplan-Meier method and compared by the Log-rank test.The univariate and multivariate analyses were performed with the Cox proportional hazard model to identify the prognostic factors.Result The mean PNI value was 47.3 ± 5.9.The mean values of the PNI in age (t =2.909,P =0.004),tumor size (t =2.227,P =0.028),tumor depth (t =3.314,P =0.001),negative lymph node (t =2.381,P =0.019),negative lymphovascular invasion (t =2.781,P =0.006) were significantly higher than those in patients without such factors.When the PNI was 47,the Youden index was maximal,with a sensitivity of 70％ and specificity of 63％.The mean age in high PNI group was significantly lower than that in low PNI group (x2 =6.443,P =0.011).Tumor infiltration depth in high PNI group was less than in low PNI group (x2 =7.394,P =0.007).The proportion of lymphovascular invasion in high PNI group was significantly lower than in low PNI group (x2 =4.540,P =0.033).The overall survival rate in high PNI group was higher than in low PNI group (P =0.002).The univariate and multivariate analyses showed that tumor location (OR,2.144 ; 95 ％ CI 1.239-3.712 ; P =0.006),lymph node metastasis (OR,4.887 ; 95 ％ CI 1.856-12.866 ; P =0.001),lymphovascular invasion (OR,1.842 ; 95％ CI 1.078-3.145 ; P =0.025) and the PNI value (OR,2.282 ; 95 ％ CI 1.344-3.874 ; P =0.002) were independent factors for predicting overall survival rate.Conclusions The PNI value is a simple and useful tool to predict the prognosis of patients with gastric cancer.