Slowing the progression of chronic kidney diseases (CKDs) requires new and effective treatment approaches. Aldosterone classically acts on the distal nephron: it facilitates sodium reabsorption, potassium secretion, and participates in blood pressure control. Recently, new targets of aldosterone have been described including the heart and the vasculature, and other kidney cells such as mesangial cells, podocytes, and renal fibroblasts. The pathophysiological implications of increased mineralocorticoid receptor (MR) expression and activation (either dependent on aldosterone or direct ligand-independent activation) and its blockade have been illustrated with ex vivo in cell cultures and in vivo in experimental animal models of CKD, including diabetic and hypertensive nephropathies, and glomerulopathies. The beneficial effects of the MR antagonists are independent of the hypertensive effect of aldosterone, indicating that blocking the activation of the MR may have unique clinical importance. Several studies have reported efficacy and safety studies with spironolactone or eplerenone in patients with kidney diseases. In this review, we discuss the recent results reported in experimental and clinical research in this field, and emphasize the direct activation of the MR that can occur in pathological states associated with CKD, even in the absence of increased circulating levels of aldosterone. © 2011 International Society of Nephrology.