Prior investigations have shown impaired endothelial function in hypertensive blacks when compared with whites. It is not clear, however, whether the difference in vascular responsiveness predates or follows the development of hypertension. Thirty-nine young black adults with a family history of essential hypertension and 41 control participants were studied for brachial artery reactivity and carotid intima-media thickness via ultrasonography, cardiac muscle mass and diastolic function by echocardiography, and biochemical analysis. There was no significant difference in brachial artery reactivity between the study groups, although women had greater reactivity than men (P=.05). Carotid intima-media thickness, left ventricular geometry, and biomarkers were equivalent between the study groups (P=not significant). Vascular imaging and biomarkers were unable to identify early evidence of endothelial dysfunction in offspring of African Americans with essential hypertension. These same studies demonstrated some early changes in vascular function based on sex.