Adiponectin, an anti-inflammatory adipocytokine, is reduced in hypertension, diabetes, and coronary artery disease (CAD). Arterial stiffness, as aortic pulse wave velocity (PWV) in hypertension and diabetes, and as augmentation index (AIx) in CAD, is independently associated with cardiovascular mortality. We explored the relationship between adiponectin and arterial stiffness in essential hypertension.Seventy-six untreated patients, 34 women, aged 47 +/- 1 years, mean +/- SEM with essential hypertension, had blood pressure (BP), carotid-femoral PWV, AIx plasma adiponectin, and proinflammatory cytokine C-reactive protein (CRP) measured using ELISA technique after an overnight fast. Results were analyzed using univariate and multiple logistic regression analysis.There was a significant positive relationship between log adiponectin and AIx (r = 0.33, P < .005) and plasma HDL-cholesterol (r = 0.40, P < .001). In contrast there were significant negative relationships with PWV (r = -0.24, P < .05), transit time (r = -0.37, P < .001), and pulse pressure amplification (r = -0.30, P < .005) in addition to waist circumference, waist-to-hip ratio, height, and weight. In a stepwise regression model, the independent predictors of AIx were heart rate, height, mean arterial pressure, age, and gender (R2= 0.69, P < .0001) with no contribution from adiponectin. However, for PWV (R2= 0.59, P < .0001) the independent determinants were mean arterial pressure, age, and adiponectin.These results show a divergent relationship between adiponectin and arterial stiffness, negative for PWV, and positive for wave reflection (AIx). Anthropomorphic factors, particularly height, weight, and heart rate may influence the relationship to the latter. Adiponectin is an independent predictor of aortic PWV but not of AIx.