Impairment of the arterial compliance or loss of Windkessel effect of elastic arteries causes increased afterload to the heart and increased pulsatile flow to the peripheral vasculatures. The former induces left ventricular hypertrophy or dysfunction and the latter induces small vessel damage or end organ dysfunction. Thus, the arterial compliance plays important roles in the course of hypertension. Therefore; it is worthwhile to measure the elastic properties of aortoarterial system in patient with hypertension. The velocity of the pressure wave along an arterial system, known as pulse wave velocity(PWV), is related to the average stiffness of an arterial segment between measurement sites. The measurement of PWV is inversely related to arterial wall distensibility, which offers a simple and potential approach. There are numerous reports which PWV is a forceful marker and predictor of the cardiovascular risk in hypertensive or other arteriosclerotic disorders. Thus, PWV measurement is recommended in patients with hypertension for early detection of organ damages or estimation of the cardiovascular risk, as well as for the evaluation of the effectiveness of the treatment as a surrogate marker.