Cardiovascular diseases such as coronary heart disease are the leading cause for morbidity and mortality in industrial countries. Current evidence shows that stiffening of the arterial wall is one major mechanism responsible for this morbidity and mortality in cardiovascular disease. Various physiological and pathophysiological parameters influence arterial stiffening including age, gender, blood pressure, smoking, and diseases such as hypertension, diabetes, renal failure, and hypercholesterolemia. Thus, the assessment of arterial stiffness has become a widely used tool to investigate the function of the arteries in epidemiologic and clinical studies. Traditionally, arterial stiffness has been assessed by pulse wave velocity, a noninvasive parameter which has been shown to predict cardiovascular mortality. In addition, pulse wave analysis has been increasingly used to determine the augmentation index, a parameter that describes the effect of pulse wave reflection on the central aortic pressure configuration. In the present review, the pathophysiological contribution of arterial stiffening for cardiovascular morbidity and mortality is described. Details of models, indices, and techniques used to evaluate stiffness will be presented. Clinical studies investigating the predictive value of stiffness markers in defining future cardiovascular risk and survival are summarized.