Inhibition of renin-angiotensin system (RAS) activity using angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers (ARBs) is beneficial in patient populations with left ventricular dysfunction or systolic heart failure (HF) and other forms of heart disease. In high-risk patients with coronary heart disease (CHD), treatment with these agents reduces the mortality rate and improves secondary outcomes. Individuals with stable CHD who are at lower risk benefit less from treatment. RAS inhibition also provides some clinical benefit to patients with diastolic HF and preserved left ventricular function. Left ventricular hypertrophy (LVH) is a strong predictor of cardiovascular events and all-cause mortality in patients with hypertension. Treatment with an ARB reduces the risk for adverse cardiovascular outcomes in patients with hypertension and LVH. The benefits correlate with regression of LVH, and the effect is independent of the degree of blood pressure lowering. Finally, studies indicate that a history of hypertension in patients who have not had a myocardial infarction (MI) increases the risk for HF after MI; the risk is decreased in patients with hypertension who receive treatment with a RAS inhibitor.