PURPOSE: There has been much debate about the significance of the CA19-9 level for predicting the prognosis of colorectal cancer patients. This study aimed to evaluate the prognostic value of the preoperative serum CA19-9 level and the CA19-9 expression in the tumor tissues of colorectal cancer patients METHODS: One hundred patients with colorectal cancer and who had been treated by resection were studied. We assessed the correlations of the preoperative serum CA19-9 level and the status of the CA19-9 immunohistochemical staining with the clinicopathologic features, including the prognosis of the patients. RESULTS: The preoperative serum CA19-9 level had significant correlation with the status of CA19-9 immunohistochemical staining. The presence of distant metastasis was significantly correlated with an elevated level of serum CA19-9. The depth of tumor, the presence of lymph node metastasis, the TNM stage and tumor cell differentiation were significantly correlated with the status of the CA19-9 immunohistochemical staining. In addition, the gross morphology, depth of tumor, the presence of lymph node metastasis, the TNM stage, the status of the CA19-9 immunohistochemical staining and the serum CEA level were correlated with survival on univariate analysis. However, multivariate analysis did not validate the status of CA19-9 immunohistochemical staining as a significantly independent predictor of the prognosis. CONCLUSION: The CA19-9 expression was frequently observed in advanced stage tumor tissue, yet its expression in tumor tissue or the preoperative CA19-9 serum level did not show independent prognostic value for colorectal cancer patients.