The present study compares the occurrence of a dry, persistent cough with doses of 80 mg of valsartan, 10 mg of lisinopril, or 25 mg of hydrochlorothiazide in patients with a history of angiotensin-converting enzyme inhibitor-induced cough. This was a randomized, double-blind, active-controlled, parallel group, multicenter trial involving 129 adult outpatients with essential hypertension. After confirmation of angiotensin-converting enzyme inhibitor-induced cough during a 2 to 4 week challenge with lisinopril (followed by a washout period of 2 weeks), patients were randomized to receive 6 weeks of double-blind treatment once daily with 80 mg valsartan, 10 mg lisinopril, or 25 mg hydrochlorothiazide. Assessments were made at baseline and after 3 and 6 weeks of treatment. Comparability of response to treatment was assessed by mean sitting diastolic and systolic blood pressure at the end of treatment. The occurrence of a dry, persistent cough was significantly less (P < 0.001) at 3 and 6 weeks with valsartan (19.5%) than with lisinopril (68.9%), with no significant difference between valsartan and hydrochlorothiazide (19.0%). There were no statistically significant differences in reduction of blood pressure among the three treatment groups. The overall incidence of adverse experiences, whether or not treatment-related, was highest for lisinopril (86.7%) compared with valsartan (57.1%), and hydrochlorothiazide (61.9%). A dry cough in the lisinopril group accounted for this difference. There were no clinically significant changes in physical signs or in results of clinical laboratory evaluations during double-blind treatment, except for from metabolic changes in 3 patients receiving hydrochlorothiazide. In hypertensive patients with a history of angiotensin-converting enzyme inhibitor-induced cough, a single daily dose of 80 mg of valsartan produced therapeutic efficacy comparable to lisinopril but with significantly less cough.