Backgrounds: The coronary endothelial function after intervention has emerged as a major concern for the long-term prognosis of coronary disease. We compared coronary endothelial function after various types of stent implantation; 3 types of drug-eluting stent (DES) and bare metal stent (BMS). Methods: Patients with one stent implantation for single lesion in left anterior descending artery were enrolled. Endothelial function was assessed only in patients with no restenosis on 6 to 9 month-follow up angiography. Endothelium-dependent vasomotion was assessed by measuring the change of diameter after intracoronary injection of acetylcholine (Ach, 10-6 mol/L). Endothelium-independent vasomotion was measured after injection of 2mg-nitrates. The measuring was done at 5 segments; near proximal and proximal, distal and far distal, and stented segments by quantitative coronary angiography. Results: Total 47 patients (42 DES, 5 BMS) were included. DES group consists of Cypher (19), TAXUS (11) and Endeavor (12 patients) groups. In stented segment, no significant vasomotion was observed. In distal and far distal segments, Cypher and TAXUS groups showed significant vasoconstriction by Ach (p<0.05 vs baseline), but Endeavor and BMS groups did not (distal: -32.6짹12.2%, -26.8짹15.1%, 1.6짹1.5%, 0.7짹0.5, far distal: -28.7짹12.3%, -29.4짹14.9%, 0.3짹2.3%, -0.9짹1.3%, for Cypher, TAXUS, Endeavor, BMS, respectively). Comparing to Endeavor and BMS groups, these vasoconstrictions of Cypher and TAXUS groups were statistically significant (p<0.05 for distal and far distal). In proximal segment, only TAXUS group showed trend of mild vasoconstriction (-4.1짹8.3%, p=0.07 vs baseline). The vasomotor response of Endeavor was similar to that of BMS group (p>0.05 for all segments). The endothelium-independent vasodilatation by nitrates was intact in all groups. Conclusion: The impairment of endothelium-dependent vasomotion in distal portion was observed in Cypher and TAXUS groups but not in Endeavor and BMS groups. Our results suggest that Cypher and TAXUS could be associated with the long-term coronary endothelial dysfunction, while Endeavor could have physiologic endothelial function similar to that of BMS.