The safety and tolerability of lisinopril have been assessed in 1,734 hypertensive patients treated with the agent in a number of clinical trials. Here we compare the clinical and laboratory adverse experiences in younger (under 55 years old) and older (at least 55 years old) patients treated with lisinopril monotherapy. The incidence of adverse experiences in these older patients was similar to that in the younger patients. A comparison also was made of clinical adverse experience data for older hypertensive patients treated either with lisinopril monotherapy or with various control agents (atenolol, metoprolol, and hydrochlorothiazide) in double-blind controlled studies. In these studies, the clinical adverse experience incidences and discontinuation percentages seen in the older patients treated with lisinopril were comparable to the data from the patients treated with the control agents. Thus, lisinopril is generally well-tolerated in older hypertensive patients, and should be considered a therapeutic option in the management of these patients.