Some consider the measurements of arterial elasticity and flow-mediated dilation to be an indirect "biomarker" of endothelial dysfunction. As such, we describe the various uses of these techniques in the evaluation of the natural history of vascular disease. These measures are potential markers of disease, as abnormalities reflect changes in the integrity of vascular structure but occur prior to the manifestation of symptomatic cardiovascular events. In this review, the natural history of arterial elasticity is discussed, and the effects of aging and inflammation are reviewed. The role that arterial elasticity and flow-mediated dilation have in predicting future cardiovascular disease, and the effects of pharmacologic agents on these measures, is also reviewed.