Objective:To investigate the number of metastasized lymph node groups (Ng) and the prognosis of gastric cancer pa-tients. Methods:Data from 1 009 patients receiving radical gastrectomy in the Cancer Center and with more than 15 lymph nodes re-trieved between January 2000 and September 2010 were included in the study. Lymph nodes were grouped by using the definition of the Japanese Research Society for Gastric Cancer (13th Japanese edition). Log-rank test and Cox regression analysis were used to ex-plore the relationship between the Ng and overall survival. Results:The metastasized lymph nodes were divided into 5 groups:1 group without lymph node metastasis (Ng0), 1 group with lymph node metastasis (Ng1), 2 groups with lymph node metastasis (Ng2), 3 to 5 groups with lymph node metastasis (Ng3), and more than 6 groups with lymph node metastasis (Ng4). The 3-year survival rates were 91.6%, 84.7%, 72.0%, 59.6%, and 43.0% for Ng0, Ng1, Ng2, Ng3, and Ng4, respectively. The 5-year survival rates were 89.9%, 82.4%, 66.9%, 54.6%, and 38.3%for Ng0, Ng1, Ng2, Ng3, and Ng4, respectively. These 3-and 5-year overall survival rates differed significantly among the groups (P<0.05). Gastric cancer patients with high Ng have low 3-year overall survival rates. Ng is an indepen-dent prognostic factor of gastric cancer. Conclusion:The concept of Ng can be a good supplement to existing UICC N staging.