Aim There is a growing evidence showing that asymmetric dimethylarginine (ADMA) and intercellular adhesion molecule-1 (ICAM-1) are markers of endothelial dysfunction and the degree of coronary collateral circulation in subjects with severe coronary artery stenosis is attributed to endothelial injury. In the present study, we examined the serum levels of ADMA and ICAM-1 in patients with severe coronary artery stenosis and furthermore to investigate the correlation between the serum levels of ADMA and ICAM-1 with the degree of coronary collateral circulation. Methods 85 patients at least with the stenosis of one vessel >95% among three main vessels of coronary artery were consecutively enrolled in the study according to angiographic estimation in our hospital from June to November in 2005. Development of collaterals was classified by Rentrop's method. According to the collateral degree, patients were divided into two groups (poorly developed collateral group: 50 patients with grade 0 and 1; well-developed collateral group:35 patients with grade 2 and 3). The levels of ADMA and ICAM-1 were also determined. Results Compared with patients with poorly developed collateral group, the levels of ADMA of patients with well developed collateral group were significantly decreased (2.23±0.59 μmol/L vs 1.79±0.57 μmol/L, P=0.001). Similarly, the levels of ICAM-1 were also markedly reduced (272.4±68.3 μg/L vs 225.0±61.9 μg/L,P=0.002). Conclusions the present data suggest that poor collateral circulation is related to elevated levels of ADMA and ICAM-1 in patients with severe coronary artery stenosis.