End-stage renal disease has become a major and costly public health problem owing primarily to an accelerating incidence of renal failure from hypertension and diabetes. In both disease groups the primary problem appears to be persistent elevation of blood pressure, and there is evidence that early and effective blood pressure control arrests the renal damage and provides continuing protection to the kidney. It is recommended that the blood pressure be controlled to levels below 150/95 mm Hg for essential hypertension and below 140/85 mm Hg for the hypertensive diabetic. Serial monitoring of renal function can be done with a graph of reciprocal (1/serum creatinine) values of annual serum creatinine measurements, particularly in groups at increased risk for end-stage renal disease. High-risk groups include blacks, older individuals, and those with serum creatinine levels > or = 1.5 micrograms/dL.