Aortic stiffness is an important predictor of cardiovascular outcome, adding value to information provided by traditional risk factors, improving risk classification, and predicting all-cause mortality. Mean arterial pressure and structural changes in the components of arterial media, are thought to be the main pathophysiological processes underlying large artery stiffening. With aging, the neat arrangement of the elastin fibers within the media is lost and the elastin fibers become thinner and fragmented, while the stiffer collagen fibers become the load bearing ones. Additional risk factors such as diabetes, inflammation, cigarette smoking, and hormonal changes are thought to exacerbate the stiffening process, although relatively little is known about the underlying pathophysiology.