The efficacy and tolerability of nicardipine retard and captopril were assessed in 174 over-60-year-olds suffering from slight or moderate essential hypertension. After 2-3 weeks of wash out the patients were randomly assigned to calcium antagonist (40 mg twice a day) or ace-inhibitor (25 mg twice a day) treatment which continued for 180 days. Monotherapy was combined with hydrochlorothiazide (12.5 mg/day) after 2 months in the event of an unsatisfactory reduction of arterial pressure in relation to basal values. Systolic and diastolic blood pressure was measured (1st and 5th Korotkoff's tone) at monthly intervals while lying and standing; heart rate was also measured using a palpatory method. Both nicardipine retard (no. 86) and captopril (no. 88) caused a significant reduction of clino- and orthostatic systolic and diastolic arterial pressure during the first two months of treatment. Respectively 70% and 51% of patients responded to treatment and the blood pressure reductions achieved using monotherapy remained unchanged during the course of the study. The association of hydrochlorothiazide resulted in a significant decrease in arterial pressure in non-responders, an effect which was observed with both nicardipine retard and captopril. No significant variation in heart rate was recorded between the two groups. Twenty-one patients in the nicardipine retard group and 16 in the captopril group suffered from slight to moderate side effects. Six patients dropped out of the nicardipine retard group and 15 patients out of the captopril group, an event for which side-effects were responsible in 1 and 3 cases respectively. In conclusion, nicardipine retard and captopril represent an efficacious form of treatment for geriatric hypertension and possess a satisfactory level of tolerability.