BACKGROUND AND PURPOSE: There are clear sex differences in the pathophysiology of aortic valve (AV) calcification in aortic stenosis (AS) patients. However, the molecular and cellular mechanisms underlying such sex differences have not been elucidated yet. Aldosterone (Aldo) promotes proteoglycan synthesis in valve interstitial cells (VICs) from mitral valves via the mineralocorticoid receptor (MR). We investigated the influence of sex in the role of Aldo/MR pathway in AV calcification in AS patients. EXPERIMENTAL APPROACH AND KEY RESULTS: MR was expressed by primary aortic VICs and in AVs from AS patients. MR expression was positively correlated with VICs activation markers in AVs from both sexes. However, MR expression was positively associated with molecules involved in AV calcification only AV from in men. Aldo enhanced VICs activation markers in cells from men and women. Interestingly, Aldo increased the expression of calcification markers only in VICs isolated from men. MR antagonism blocked (spironolactone) all the above effects. Cytokine arrays showed intercellular adhesion molecule (ICAM)-1 and osteopontin to be specifically increased by Aldo in male VICs. In AVs from men, MR expression positively associated with both ICAM-1 and osteopontin. CONCLUSION AND IMPLICATIONS: These findings demonstrate that the Aldo/MR pathway could play a role in early stages of AS by promoting VICs activation and ulterior calcification. Importantly, Aldo/MR pathway is involved in early AV calcification only in men. Accordingly, MR antagonism emerges as a new sex-specific pharmacological treatment to prevent AV calcification in men.