Calcium antagonists exert several characteristic effects on the kidney that potentiate their antihypertensive effect. The objective of the present study was to investigate the effectiveness of nitrendipine in the presence of different degrees of renal impairment. Two groups of hypertensive patients were included in the study. Group 1:10 patients with arterial hypertension secondary to chronic renal parenchymatous disease and adequately controlled with a diuretic and/or a beta-blocker who were switched to nitrendipine. These patients were then followed monthly for 1 year. Group 2:24 patients diagnosed as having essential hypertension who presented values of urinary albumin excretion above 30 mg/day after a minimum of 3 years of adequate blood pressure control with a diuretic and/or a beta-blocker. Patients were randomly assigned to continue with the same therapy or to switch to nitrendipine for 1 year. In both groups nitrendipine was as efficacious as standard therapy for controlling blood pressure and did not induce changes in renal hemodynamics. Nitrendipine did not modify the level of proteinuria in group 1, nor the urinary excretion of albumin in group 2. These results seem to indicate that nitrendipine can be safely used in patients with arterial hypertension and different degrees of renal function impairment.