Hypertension with hypokalemia, metabolic alkalosis, and suppressed plasma renin activity defines mineralocorticoid hypertension. Mineralocorticoid hypertension is the consequence of an overactivity of the epithelial sodium channel expressed at the apical membrane of renal cells in the distal nephron. This is usually the case when the mineralocorticoid receptor is activated by its physiologic substrate aldosterone. The best known form of mineralocorticoid hypertension is an aldosterone-producing adrenal tumor leading to primary aldosteronism. Primary aldosteronism can also be caused by unilateral or bilateral adrenal hyperplasia and rarely adrenal carcinoma. Interestingly, most of the inherited monogenic disorders associated with hypertension involve an excessive activation of the mineralocorticoid axis. In some of these disorders, mineralocorticoid hypertension results from activation of the mineralocorticoid receptor by other steroids (cortisol, deoxycorticosterone), by primary activation of the receptor itself, or by constitutive overactivity of the renal epithelial sodium channel. The present review addresses the physiology and significance of the key players of the mineralocorticoid axis, placing emphasis on the conditions leading to mineralocorticoid hypertension.