To investigate the expressions and changes of serum soluble intercellular adhesion molecule-1 (sICAM-1) in lung cancer patients before and after operation and the roles of sICAM-1 in differential diagnosis, metastatic potential, and prognosis. Methods From 2002 to 2003, a total of 17 samples of lung carcinoma tissues and sera were studied. The other 11 non-cancer patients were employed as the controls. Cell surface sICAM-1 levels were analyzed by immunohistochemistry method and ELISA. Results The serum sICAM-1 concentration in the cancer patients was (432.0?124.4) ng/ml. In the controls, however, the serum concentration of sICAM-1 was (262.3?77.7) ng/ml. In patients with lung cancer, the serum concentration of sICAM-1 was significantly higher than that of the controls (P0.05). Conclusion The serum sICAM-1 concentrations in lung cancer patients may play an important role in staging and may also serve as a useful indicator of advanced disease.