The purpose of this study was to evaluate the validity of brachial-ankle pulse wave velocity (baPWV) and the cardio-ankle vascular index (CAVI) as measures of arterial stiffness in hemodialysis (HD) patients. We studied 160 consecutively enrolled HD patients (mean age: 59+/-13 years; 91 male patients). We measured baPWV and CAVI using a VaSera VS-1000, maximum intima-media thickness (max IMT) of the carotid artery by ultrasonography and blood renal and lipid parameters. As a control, baPWV and CAVI were also measured in age- and gender-matched healthy volunteers. Both baPWV and CAVI were significantly higher in HD patients than in controls (baPWV: 1698+/-355 vs. 1454+/-263 cm s(-1), P<0.0001; CAVI: 9.3+/-1.4 vs. 8.9+/-1.2, P<0.01). BaPWV correlated positively with age (r=0.549, P<0.0001), systolic blood pressure (SBP) (r=0.510, P<0.0001), diastolic blood pressure (r=0.203, P<0.0001), pulse pressure (PP) (r=0.499, P<0.0001), Kt V(-1) (r=0.221, P<0.01), Brinkman index (r=0.186, P<0.05) and max IMT (r=0.285, P<0.001). CAVI also correlated positively with age (r=0.562, P<0.0001), SBP (r=0.395, P<0.0001), PP (r=0.490, P<0.0001), Kt V(-1) (r=0.216, P<0.01), Brinkman index (r=0.238, P<0.01) and max IMT (r=0.280, P<0.001). Multiple regression analysis demonstrated baPWV and CAVI correlated independently with age and SBP. Receiver operating characteristics (ROC) curve analysis demonstrated that baPWV and CAVI had similar power to predict increases in max IMT. We also measured baPWV and CAVI immediately before and after HD, and showed CAVI was influenced by changes in water volume. Both baPWV and CAVI are therefore useful indices of arterial stiffness in HD patients.