Background- Previous studies have demonstrated that adiponectin has an anti-atherogenic effect and endothelial dysfunction plays a major role in pathogenesis of atherosclerosis. In this study, we investigated the relationship between plasma concentration of adiponectin and endothelial dysfunction in healthy premenopausal women. Methods and Results- We studied a total of 65 premenopausal women (aged 20 - 45). We analyzed the plasma adiponectin concentrations, metabolic variables, and endothelial function between obese (n=23, BMI ���28 Kg/m2) and non-obese group (n=42, BMI < 28 Kg/m2). Endothelial function was measured by pulse-wave analysis (PWA) combined with provocative pharmacologic testing. The changes of augmentation index after salbutamol administration (AIx) significantly reduced in obese women compared with non-obese women (-8.0 짹 5.5 VS. -13.8 짹 7.3%, P < 0.001). In contrast, those after NTG administration did not differ significantly (-29.4 짹8.2 VS. -29.7 짹 8.3%). Adiponectin concentrations were significantly lower in obese women than those of non-obese women (3.24 짹 1.08 vs. 4.90 짹 2.06 關g/ml, P < 0.01). The plasma concentrations of adiponectin were positively correlated with AIx in obese women (r=0.66, p < 0.001). However, there were no significant correlations between adiponectin and AIx in non-obese women. In multiple analyses, plasma adiponectin concentrations were major variable influencing AIx in obese group (棺=0.47, p < 0.05, R짼 = 0.37). Conclusions- These results suggest that the decreased plasma adiponectin concentrations in obese women may be an indicator of endothelial dysfunction.