Aldosterone is the main hormone regulating the water and electrolyte balance of the organism. It is produced and secreted by zona glomerulosa of the adrenal gland cortex, cardiomyocytes as well as by cells of the blood vessel wall. The article is the review of contemporary knowledge of the role of aldosterone in physiology and pathophysiology of cardiovascular system. The authors describe the nuclear and membrane mechanisms of endothelial action of aldosterone, especially their role in the development of cardiovascular system pathologies. New therapeutic indications for aldosterone receptor antagonists are also discussed.