We evaluated in 214 patients with primary colorectal cancer the prognostic value of the preoperative serum levels of CEA and CA195. For CEA these levels were above the cutoff of 6 ng/ml in 31.3% of patients, whereas for CA195 they were higher than 12 U/ml in 35.9% of patients. The simultaneous use of both antigens increased the sensitivity to 49%, which was significantly higher than that of CEA (p < 0.001) and CA195 (p < 0.01) taken singly. The mean preoperative CEA levels were significantly (p < 0.001) correlated with Dukes' stage only, while there was a significant correlation between preoperative serum levels of CA195 and Dukes' stage (p < 0.001), grade of differentiation (p < 0.01) and tumor location (p < 0.05). The results indicated that high preoperative serum levels of CEA and CA195 were associated with a shorter overall survival (p < 0.0001). In addition, separate Cox multivariate analysis showed that preoperative CA195 was, after Dukes' stage, the strongest factor to predict overall survival (p < 0.0001).