Abstract: Objective To investigate the prognostic factors of stage Ⅲ (pT1-4N1-2M0) colon cancer, and discuss the feasibility of preoperative prognosis evaluation. Methods Clinicopathologic data of patients with stage Ⅲ colon cancer treated with curative surgery alone from January 2004 to June 2008 in Peking University Cancer Hospital was retrospectively reviewed,to analyze the prognostic factors of demographics, clinical, histopathologic, and laboratory data. Univariate and multivariate analysis were conducted to identify prognostic factors associated with 3-year disease-free survival (3yr DFS). Results There were 131 valid cases reviewed in this study, the 3yr DFS was 63.4%. Univariate analysis showed that preoperative CEA level >5 ng/ml, poor differentiation, tumor diameter ≥5 cm, higher N stage, TNM stage and lymphaticvessel invasion were the poor prognostic factors of patients with stage Ⅲ colon cancer (P<0.05). Multivariate analysis showed that preoperative CEA level (P=0.000, RR=2.832, 1.755-6.023), higher N stage(P=0.001, RR=1.456, 1.522-4.984), tumor diameter≥5 cm(P=0.015, RR=1.663, 1.155-3.871) were the independent prognostic factors for 3yr DFS. Conclusion According to the prognostic risk factors of preoperative CEA level,higher N stage and tumor diameter ≥5 cm, more accurate risk stratifi cation more intensive treatment and more closely surveillance could be conducted in patients with stage Ⅲ colon cancer.