Objective To investigate the relationship between hypoxia-inducible factor-1α(HIF-1α) and construction of collateral circulation in patients with coronary artery disease. Methods Collateral vessels were determined in 96 patients with≥70% narrowing of at least one coronary artery without prior revascularization,42 patients with coronary artery collaterals and 54 patients with no coronary artery collaterals.Another 50 cases with normal coronary arteries were selected as control.The levels of HIF-lα expression in monocytes and lymphocytes were tested by immunohistochemistry (IHC) and Western blot.Results Compared to the controls,the patients had higher expression of HIF-1α(P<0.01).Higher HIF-1α expression was found in patients with collaterals than in those without collaterals (P<0.01).Positive correlation was observed between the expression of HIF-1α protein and collateral score (r1=0.78,r2=0.84,P<0.01).Conclusion HIF-1α expression in circulating monocytes and lymphocytes are associated with collateral circulation.Detection HIF-1α might be helpful in the prognosis of patients with coronary artery disease.