The angiotensin-converting enzyme inhibitor, perindopril erbumine, has been approved for use in the United States only recently but has been studied extensively worldwide over the last decade. Placebo-controlled trials in a wide range of patients with hypertension, including the elderly, those with isolated systolic hypertension, and those with concomitant diseases such as hyperlipidemia, diabetes, cardiac arrhythmia, peripheral arterial occlusive disease, nephropathy with proteinuria, and chronic obstructive pulmonary disease, have shown that perindopril is highly effective in lowering both systolic and diastolic blood pressure (BP). Studies in which BP has been monitored for 24-hour intervals show that perindopril (1) has a gradual onset of action, (2) provides smooth BP control over its once-daily dosing interval, (3) has a trough-peak ratio of about 1, and (4) maintains its antihypertensive efficacy despite missed doses. Perindopril increases arterial compliance and reverses left ventricular hypertrophy in hypertensive patients. Both of these effects are at least partly independent of its ability to lower BP. Perindopril is safe and well tolerated in patients with hypertension. Rates of adverse events and discontinuation because of such events are low.