We report the preliminary findings in the first 12 patients enrolled in a double-blind randomized placebo-controlled study of the antianginal effect of the new angiotensin-converting enzyme inhibitor, cilazapril (2.5 mg once daily) in patients with both hypertension and angina pectoris. After 3 weeks of treatment, placebo had no effect whereas cilazapril significantly prolonged exercise duration. In 2 of the patients on cilazapril, exercise duration was markedly prolonged from 387 to 534 and 352 to 556 s. The maximal ST segment depression was unaltered. It is suggested that in selected patients with both hypertension and angina pectoris cilazapril may have an antianginal effect. A larger study is now underway.