The antihypertensive efficacy and safety of mibefradil and nifedipine SR were compared in 143 patients with chronic renal failure and mild-to-moderate hypertension in a multicenter, double-blind, randomized, parallel-design study. At treatment week 12, a significantly greater decrease in sitting diastolic blood pressure (SDBP) was seen with mibefradil than with nifedipine SR (12.8 mmHg vs 8.1 mmHg, respectively; p = 0.014). A significantly greater number of mibefradil-treated patients achieved normalization of SDBP by week 12 (62% vs 37%; p < 0.01). The changes in renal function parameters and the incidence of adverse events were similar in both groups. In this population, 12 weeks of treatment with mibefradil were more effective than nifedipine SR for lowering blood pressure and had similar effects on renal function parameters.