Background: The assessment of diastolic function is an important part of a routine examination and provides a predictive value for cardiovascular outcome in patients with heart failure. We assessed the utility of novel diastolic index using three-dimensional (3D) tracking by comparing other conventional diastolic parameters and arterial stiffness in the patients with hypertension. Methods: 3D wall motion tracking (Artida^TM, , Toshiba) was used to measure area strain in 61 hypertensive patients. 3D Diastolic index (3D-DI) was calculated by the percentile change of global area strain during the first one-third of diastolic period. Conventional echocardiographic parameters including left ventricular mass (LVMI) and left atrial volume indices (LAVI) were assessed using 2D echocardiography. Arterial stiffness was evaluated by acquiring pulse wave velocity and augmentation index (AIx) with radial artery applanation tonometry (SphygomoCorR, AtCor). The relationship between diastolic index and conventional echocardiographic parameters and arterial stiffness was assessed. Results: In patients with decreased 3D-DI, LVMI, LAVI and isovolumic relaxation time (IVRT) were significantly increased, whereas E/A ratio and E��� were reduced (r=-0.35, p=0.01 for LVMI; r=-0.53, p=0.001 for LAVI; r=-0.38, p=0.008 for IVRT; r=0.43, p=0.002 for E/A ratio; r=0.34, p=0.02 for E���). In addition, lower 3D-DI was associated with increased AIx (r=-0.36, p=0.02 for AIx) but not with pulse wave velocity. Conclusions: 3D-DI was associated with LVMI, LAVI and AIx, suggesting that this novel index might provide additional information in assessing diastolic function in the hypertensive patients.