Leptin may be a link in the relationship of obesity with hypertension. We evaluated associations of leptin with blood pressure (BP) in 54 normotensive and 114 hypertensive African American individuals. Plasma leptin was higher (P <.03) in hypertensive women than in normotensive women, although body mass index did not differ (30.5 +/- 0.5 v 30.2 +/- 0.8 kg/m(2)). After adjusting for obesity and insulin resistance, there were no significant relationships between leptin and BP; however, leptin independently predicted 28% of the variability of heart rate in hypertensive men (P <.01) and 18% of the variability of lithium clearance in hypertensive women (P <.01). Thus, in these obese hypertensive African American women, there is no direct or independent association of leptin with BP. However, leptin may contribute to hypertension in these women by increasing renal tubular sodium reabsorption.