Arterial stiffness is a vascular measure that has been reported to predict cardiovascular events. It is important to measure arterial stiffness in order to determine current vascular status and treatment strategy. Brachial-ankle pulse wave velocity (baPWV) is a unique measure of systemic arterial stiffness that is measured by brachial and tibial arterial wave analyses. Measurement of baPWV is easy and is reproducible. For more than a decade, this measure has been used broadly in East Asian countries. Meta-analysis of cohort studies conducted in the general population with hypertension, diabetes, or end-stage renal disease, and other high-risk individuals have shown that a 1 m/s increase in baPWV is associated with 12% increase in the risk of cardiovascular events. Thus, the Japanese Circulation Society has proposed that a baPWV of 1800 cm/s is a threshold for high-risk category. For baPWV to be clinically applicable, we must confirm that circulation of the lower limbs are normal by examining brachial ankle blood pressure index. In cases of peripheral arterial disease, the reliability of baPWV measurement is attenuated. To further confirm the clinical usefulness of this measure, we need to examine the hypothesis that baPWV-guided therapy could improve prognosis in high-risk patients.