We investigated the effects of different antihypertensive drugs on the ambulatory arterial stiffness index (AASI), pulse pressure (PP), the arterio-ventricular coupling index (AVCI) and aortic pulse wave velocity (aPWV). After a 4-week placebo period, 94 and 107 patients with uncomplicated hypertension were randomly assigned to treatment with atenolol (AT) at dosage of 50 mg per day or perindopril/indapamide (PER/IND) at dosage of 2/0.6 mg per day for 1 year. From each patient's 24-h ambulatory blood pressure (BP) recording, we determined the 24-h systolic and diastolic BPs. We computed PP as the difference between 24-h systolic and diastolic BP, AASI as unity minus the regression slope of diastolic on systolic BP, and AVCI as (T/τ)/(1+2T/3τ), where T is the heart period in seconds and τ is the decay time of aortic BP during diastole. On AT compared with PER/IND, with adjustments applied for covariables, 24-h systolic BP (-9.5 vs. -13.7 mm Hg; P=0.009) and 24-h PP (-1.02 vs. -6.53 mm Hg; P<0.001) decreased less and AVCI lengthened more (+0.019 vs. -0.008; P<0.001). The changes in AASI (-0.001 vs. -0.014; P=0.44) and aPWV (-0.89 vs. -0.69 m s(-1); P=0.45) were similar in the two treatment groups. AASI and aPWV showed significant concordance (r=0.21, P=0.003) after adjustment for covariables. On administration of antihypertensive drugs with different hemodynamic profiles, AASI and aPWV behaved similarly. The similarity in the findings for aPWV and AASI support the use of AASI as an index reflecting the arterial stiffness.Hypertension Research advance online publication, 13 January 2011; doi:10.1038/hr.2010.256.