Children from an entire biracial geographical population were examined for blood pressure. A sample of 278 children, stratified by diastolic blood pressure, was reexamined 1 to 2 years later. Dopamine beta-hydroxylase, renin activity, and resting heart rate were observed in black and white children. In the group with high blood pressure, whites had higher heart rates and greater renin activity than blacks. Dopamine beta-hydroxylase concentrations in blacks were lower than in whites over the entire spectrum of blood pressure levels. High blood pressure seems to have a different metabolic background in the two races which may influence the early natural history of essential hypertension. Therefore, the rationale of prevention, and possibly treatment, of early hypertension in blacks and whites may differ.