Background: Central (aortic) blood pressure (BP) has been reported as a more powerful indicator to predict cardiovascular risk than peripheral (brarchial) BP. Also, increased left ventricular mass index (LVMI) and its change during treatment can predict cardiovascular complications in hypertensive subjects. However, the relationship between aortic or peripheral BP and LVMI is not clear especially in first diagnosed hypertensive subjects. We purposed to compare the relationship of LVMI with central and peripheral BP parameters. Methods: We studied 111 patients who diagnosed hypertension for the first time without any medical history including diabetes (mean age: 47짹10 years, 72 males). Subjects with heart failure, any significant valvular disease or cardiomyopathy on echocardiogram were excluded. Peripheral BP was measured by automatic sphygmomanometer at brachial artery and central BP was measured by analysis of non-invasive radial artery pulse wave using automated applanation tonometry. The LVMI was calculated from M-mode echocardiographic data and body surface area. To avoid multiple co-linearity among BP parameters, multiple regressions predicting LVMI were done four times. Results: Baseline central and peripheral systolic BP (SBP) were 136짹17 and 150짹18mmHg (p<0.001) and each mean pulse pressure (PP) was 41짹11 and 53짹13mmHg respectively (p<0.001). Mean PP difference was 11.7짹12.0mmHg and mean LVMI was 109짹22g. The LVMI was positively correlated with age, peripheral SBP & PP, central SBP & PP, and carotid intima-media thickeness (r=0.231, 0.276, 0.283, 0.248, 0.343, 0.259 respectively, each p<0.05). But, PP difference was not significantly correlated (p=0.915). Although central and peripheral systolic and pulse pressures were still significantly related to LVMI after adjustment for age in the four different analyses, central PP was stronger predictor than peripheral PP (棺 coefficient=0.311, p=0.001 vs. 0.281, p=003). Conclusion: Left ventricular mass index, which is one of useful indicators for predict cardiovascular risk and outcome of hypertension, is independently and positively associated with blood pressure parameters. Central pulse pressure is particularly more strongly related with LVMI than peripheral BP parameters. Keywords: Hypertension, Central pulse pressure, Left ventricular mass index