We studied the correlation between serum soluble intercellular molecule 1 (sICAM-1) and clinicopathological features in patients with gastric cancer. The impact of sICAM-1 on prognosis was also evaluated. The sera from 224 patients with gastric cancer, 44 healthy individuals, and 35 patients with benign gastrointestinal diseases (4 patients with submucosal stomach tumors, 6 patients with gastric ulcers, 1 patient with Crohn disease, 2 patients with ulcerative colitis, 7 patients with gall stones, 5 patients with chronic pancreatitis, and 10 patients with liver cirrhosis) were measured for sICAM-1 titer using a sandwich enzyme immunoassay method. There was no correlation between the serum titer of sICAM-1 and the age or gender of healthy controls. Among patients with benign gastrointestinal diseases, the patients with liver cirrhosis had a significantly higher mean serum sICAM-1 titer than that of healthy controls (P < 0.0001). The mean serum sICAM-1 titer of all patients with gastric cancer was not significantly different from that of healthy controls. However, among the patients with stage IV and recurrent disease, the serum sICAM-1 titer of those with hematogenous metastasis was significantly higher than that of patients without hematogenous metastasis (P = 0.001). The patients with a high serum sICAM-1 titer of more than 304 ng/ml (mean of healthy controls plus SD) showed a significantly worse prognosis than patients with a low serum sICAM-1 titer (P = 0.010). Nevertheless, serum sICAM-1 titer was not an independent predictor of prognosis by multivariate analysis. In conclusion, serum sICAM-1 cannot be used as a tumor marker for early diagnosis. However, sICAM-1 in sera may still be worthwhile to measure for monitoring hematogenous metastasis.