Hypertension is a major risk factor for cardiovascular disease, and small reductions in blood pressure can have a substantial impact on outcome. Effective control of hypertension per se is important in reducing morbidity and mortality, but there is growing evidence that the class of drug used in treatment may affect patient outcomes. The Heart Outcomes Prevention Evaluation (HOPE) trial provided evidence that angiotensin converting enzyme inhibitors (ACEI), agents that inhibit the renin-angiotensin system (RAS), are particularly effective in reducing the risk of cardiovascular events in a wide range of patients. These beneficial effects of ACEI may be independent of antihypertensive effect. Angiotensin receptor blockers (ARB) are the newest class of antihypertensive drug to enter clinical use. By blocking the angiotensin II type 1 receptor, ARB achieve more complete blockade of the RAS than ACEI. The ARB also have a substantially better side effect profile than ACEI, and early evidence suggests that ARB are beneficial in combating hypertension-related target organ damage. These favorable characteristics suggest that ARB should be considered as first-line treatment for hypertension. Based on comparative antihypertensive efficacy, olmesartan, a new ARB, may represent a significant addition to this drug class.