Renal function and life expectancy can be improved by aggressive antihypertensive therapy in severe hypertension. However, most reports of severe hypertension and renal failure concern primary hypertensive states. 3 cases of primary renal disease, 1 glomerular, 1 obstructive and 1 of chronic pyelonephritis, are described here. In all 3 cases, severe hypertension and renal failure were present. Adequate reduction in blood pressure resulted in substantial improvement in renal function.