The antihypertensive effect of ramipril, a new angiotensin-converting enzyme (ACE) inhibitor, was evaluated and compared to enalapril in a double-blind, randomized, controlled trial. Subjects received either 2.5, 5, or 10 mg of ramipril given once daily or 5, 10, or 20 mg of enalapril once daily for 4 weeks. Significant decreases from baseline in supine and standing diastolic blood pressures were seen in all dosage groups at end point. There were significant decreases at end point for supine and standing systolic blood pressures at the higher doses. Side effects were minimal and were similar for all treatment groups.