This study will evaluate efficacy and safety data for benazepril/hydrochlorothiazide in adult Chinese patients with mild to moderate essential hypertension. Patients whose blood pressure is not adequately controlled with benazepril monotherapy during a 4 week run-in period will be randomly allocated to double blind treatment over 8 weeks with either a combination of benazepril/hydrochlorothiazide per day or continuation of benazepril per day.