A single-blind, run-in, randomized, double-blind, parallel-group, placebo-controlled comparison trial was conducted to assess the safety and efficacy of low-dose amlodipine 2.5 mg daily, low-dose benazepril 10 mg daily, and the combination of the two drugs at the same doses used once daily in patients (n = 401) with mild to moderate (stages I and II) systemic hypertension. Both monotherapy regimens were shown to significantly reduce both systolic and diastolic blood pressure compared with baseline placebo values, and the combination regimen was shown to be superior in lowering systolic and diastolic blood pressure when compared with either of the monotherapy regimens. The combination therapy also resulted in a greater percentage of patients having successful clinical response in mean sitting diastolic blood pressure. The amlodipine and benazepril regimen was also shown to be associated with a similar incidence of adverse experiences as the active monotherapy or placebo regimens, although the group given combination therapy appeared to have a lower incidence of edema than the group given amlodipine alone. Low-dose amlodipine (2.5 mg) plus benazepril (10 mg) provides greater blood-pressure-lowering efficacy than either monotherapy, and has an excellent safety profile.