OBJECTIVE Serum soluble intercellular adhesion molecule-1 (sICAM-1) and total sialic acid (TSA) are related to the metastatic potential of cancer cells. The purpose of the present investigation was to determine sICAM-1 and TSA levels in colorectal carcinoma and correlate their levels with the cancer stage. METHODS The sera from 65 patients with colorectal cancer (18 at Dukes' B, 24 at Dukes' C, 23 at Dukes' D) were extracted before treatment. The concentrations of sICAM-1 and TSA were measured by enzyme-linked immunoassay and the thiobarbituric acid method, respectively, and compared with those from a healthy control group (n = 42). RESULTS Mean serum sICAM-1 and TSA levels were found to be higher in the total patient group than in the control group (P < 0.0001). The concentrations of sICAM-1 and TSA were significantly higher in patients with Dukes' C and Dukes' D. The correlations between sICAM-1 and TSA became more significant as the stage of the disease increased (r = 0.58, P < 0.05 in Dukes' B, r = 0.88, P < 0.01 in Dukes' C and r = 0.81, P < 0.01 in Dukes' D). CONCLUSIONS The results of this investigation indicate that sICAM-1 and TSA are the best of the tested markers. These markers should prove useful for monitoring malignant disease stage and for evaluating the effectiveness of various therapeutic approaches for colorectal carcinomas.