The antihypertensive efficacy and tolerability of a fixed combination of benazepril (10 mg) and low-dose amlodipine (2.5 mg) were assessed in 24 patients (mean age, 43.9 years) with uncomplicated mild to moderate essential hypertension [supine diastolic blood pressure (DBP) > or = 95 and < or = 120 mm Hg)]. After 2 weeks of washout taking placebo, patients were randomized to receive the fixed combination or placebo, both administered once daily for 3 weeks, according to a double-blind, crossover design. Patients were checked at the end of the washout period and every 3 weeks thereafter. At each visit, 24-h ambulatory BP monitoring (ABPM) was performed by a noninvasive device (Spacelabs 90207); casual BP (by mercury sphygmomanometer), heart rate (HR), and body weight also were measured. The fixed combination significantly reduced systolic (SBP) and DBP values throughout the 24 h as compared with placebo, without affecting the normal BP circadian variability. The antihypertensive effect of the fixed combination could be observed to a similar extent during the day and night and was still significant 24 h after dosing. HR and body weight were not affected by the treatment. The fixed combination of benazepril 10 mg/amlodipine 2.5 mg was well tolerated, and no patient withdrew from the study because of side effects.