PURPOSE: Colorectal carcinomas are one of the most common malignant tumors in western countries. In Korea, it is the fourth common malignancy and the incidence has been rising over the past 10 years. We studied respectively to analyse prognostic factors in patients with colorectal cancer. MATERIALS AND METHODS: 893 patients with primary colorectal carcinomas who were operated at our hospital between 1989 and 1997 were reviewed. We examined possible prognostic factors such as, age and sex of patients, size and location of tumors, preoperative serum CEA and CA19-9 level, modified Dukes stage, operative methods, and lymph node metastases. RESULTS: Overall 5-year survival rate was 61.8%. The 5-year survival rates in modified Dukes stage A, Bl, B2, Cl, C2 and D were 100%, 89.4%, 72.5%, 63.3%, 55.1% and 21.5%, respectively. Univariate analysis showed that age, modified Dukes stage, preoperative serum CEA and CA19-9 level, and lymphatic metastases were significant factors. The size of tumor was a significant factor in rectal carcinomas but not in colon carcinomas. In extraperitoneal rectal carcinomas, there were no survival differences between low anterior resection and abdominoperineal resection groups. Preoperative serum CEA level and modified Dukes' stage were significant in multivariate analysis, CONCLUSION: Modified Dukes stage, preoperative serum CEA were independent prognostic factors for patients with colorectal cancer.