Aldosterone blockade has been shown to be effective in reducing mortality in patients who have severe heart failure because of systolic left ventricular dysfunction (SLVD) and those who have heart failure and SLVD post-myocardial infarction. Aldosterone blockade also may be beneficial in patients who have New York Heart Association class II heart failure, asymptomatic left ventricular dysfunction, and heart failure with preserved or normal left ventricular function. Considering the beneficial effects of aldosterone blockade on improving nitric oxide availability, endothelial function, and atherosclerosis, it can also be postulated that an aldosterone blockade would add to the benefits of an angiotensin-converting enzyme inhibitor in patients who have coronary artery disease. However, these hypotheses must be confirmed in well-designed, large-scale, prospectively randomized studies.