Background: The aim of this study was to investigate differences of endothelial function assessed by flow-mediated dilation (FMD), which is an dependent predictor for endothelial function and nitrate-mediated dilation (NMD), which is an independent factor for endothelial function of brachial artery between vasospastic angina (VA) and stable angina (SA). Methods: One hundred twenty three patients were divided into 3 groups according to coronary angiographic findings: no significant coronary artery disease (CAD) and no ergnovine-induced coronary artery spasm (control group: n=40, 52.6짹10.3 years, 22 males), ergonovine-induced coronary artery spasm without significant coronary stenosis (VA group: n=43, 53.7짹12.0 years, 18 males) and stable angina due to significant CAD (SA group: n=40, 54.8짹10.6 years, 28 males). FMD and NMD were measured in the same day morning before diagnostic coronary angiogram. Results: The FMD was 9.3짹4.2 % in control group, 9.2짹4.4 % in VA group, and 7.2짹3.4 % in SA group. The FMD was significantly decreased in the SA group compared with control group (p=0.045). The NMD was 21.2짹6.4 % in control group, 23.6짹9.5 % in VA group, and 17.8짹9.5 % in SA group. The NMD was significantly increased in the VA group compared with control group (p=0.011). Conclusion : The flow-mediated endothelial function was impaired in stable angina, but maintained in variant angina with hyper-responsiveness to nitrate.