Hyperaldosteronism is associated with endothelial dysfunction and impaired vascular reactivity in patients with hypertension or congestive heart failure. When present, endothelial dysfunction is an independent predictor of adverse cardiovascular events. The mineralocorticoid receptor (MR) antagonists spironolactone and eplerenone reduce morbidity and mortality, and it has been suggested that this occurs, in part, as a result of improved vascular function. The routine use of MR antagonists in patients with cardiovascular disease, however, is limited by the development of gynecomastia with spironolactone use and hyperkalemia with the use of both agents. Therefore, the development of newer agents with more favorable side-effect profiles is needed.