OBJECTIVE We evaluated the prognostic value of the preoperative serum carcinoembryonic antigen (CEA) level in patients with colon cancer. METHODS We reviewed 474 patients who underwent potentially curative resection for nonmetastatic colon cancer. Patients were categorized into two groups according to the preoperative serum CEA level: low CEA (<5 ng/ml) and high CEA (>or=5 ng/ml) groups. RESULTS During the median 45-month follow-up period, the 5-year overall and disease-free survival rates for patients with a low CEA level were 81.7% and 82.4%, respectively, which were significantly higher than the rates for those with a high CEA level (69.9%; P = 0.011 and 70.6%; P = 0.002, respectively). A multivariate analysis revealed that a preoperative serum CEA level was a significant independent prognostic factor for both overall survival (P = 0.021) and disease-free survival (P = 0.026). Both the overall and disease-free survival rates in patients with stage II tumors differed significantly between the low and high CEA groups, whereas the rates did not different between those with stage I and III tumors. CONCLUSIONS Preoperative serum CEA is a reliable predictor of recurrence and survival after curative surgery in patients with colon cancer, particularly in those classified as having stage II disease.