Calcific aortic valve disease (CAVD) describes a chronic and slowly progressive condition that results in impaired functioning of the aortic valves due to pathological calcification of the valve leaflets. Recent epidemiological studies suggest a rising incidence and mortality from this condition making this a global health problem. CAVD shares many risk factors for atherosclerosis and early lesions of CAVD resemble atherosclerotic plaques. However, it is now apparent that CAVD is a distinct disease entity. The complex and harsh haemodynamic environment to which the aortic valve is exposed may act as the initial trigger for a cascade of downstream cellular and molecular pathways including lipid deposition, inflammation, extracellular matrix degradation and remodeling, and finally calcification. The effectors of calcification are two heterogenic cell types integral to the normal functioning of the aortic valve, the valvular endothelial and interstitial cells that develop an osteogenic phenotype. This review draws a summary of the pathophysiological mechanisms thought to be involved in CAVD.