Twenty-four subjects with mild to moderate essential hypertension completed this 9-wk parallel, randomized, double-blind study of the antihypertensive effects of verapamil (V) (240 to 480 mg%) and propranolol (P) (120 to 360 mg%). V lowered systolic and diastolic blood pressures in all postural positions, with an average reduction of 20/16 mm Hg. With the exception of standing systolic blood pressure, P also lowered systolic and diastolic blood pressures in all postural positions, with an average reduction of 9/11 mm Hg. Differences between V and P were significant only for sitting systolic blood pressure. Heart rate was decreased by P but was not affected by V. The PR interval was prolonged by V. Plasma levels of V and P were directly related to dose. Plasma levels of V were linearly related to those of its major metabolite, norverapamil (r = 0.81). There was no correlation between clinical response and the dose or plasma level of V or P, but all subjects who received 480 mg% V had an average blood pressure reduction of 20/16 mm Hg and plasma levels of the parent drug above 200 ng/ml. V is an effective antihypertensive for mild to moderate essential hypertension. Constipation, pedal edema, and a maculopapular rash were reported as side effects of V.