The renin-angiotensin system exerts a cardinal role in the maintenance of blood pressure and in the regulation of water and sodium excretion through its multiple effects on the vasculature, the kidneys, the heart, the adrenal glands and the brain. Over the last 30 years, blockade of the renin-angiotensin cascade with angiotensin converting enzyme (ACE) inhibitors has proved to be a major advance in the treatment of hypertension and the prevention of its cardiovascular complications. The recent development of specific, orally active angiotensin AT(1) receptor antagonists has provided further insights into the role of the various angiotensin receptor subtypes in the regulation of blood pressure. Even more importantly, these new specific antagonists have provided the opportunity to effectively block the renin-angiotensin system in hypertensive patients with an efficacy comparable to that of other antihypertensive agents but with a tolerability profile similar to that of placebo. Numerous clinical studies have now demonstrated the potential benefits of these agents in the management of essential hypertension. We now need to know whether these agents are capable of reducing the cardiovascular morbidity and mortality associated with hypertension. To this purpose, several large clinical trials are ongoing and we are eager to read their results.