Blockade of the renin-angiotensin system by angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers has been shown to be effective in treating hypertension and heart failure. There are currently seven angiotensin II receptor blockers in clinical practice, olmesartan medoxomil being the newest agent in the class. This article reviews the pharmacokinetics, pharmacodynamics, safety, efficacy, clinical use, dosing and cost of olmesartan medoxomil. The information given here is based on published data from human studies regarding the efficacy and safety of this drug, as well as studies comparing it with other drugs. The use of olmesartan medoxomil (10-40 mg) has consistently helped achieve a double-digit reduction both in systolic and diastolic blood pressure, a reduction which is maintained for one year. The data on its use for heart failure and atherosclerosis are limited and mostly experimental. It is an effective and well-tolerated agent, with a long duration of action, and single daily dose may be used to treat hypertension.