Left ventricular hypertrophy (LVH) is the most frequent cardiac abnormality in patients with end-stage renal disease (ESRD). Recent studies have shown that arterial stiffness is associated with mediacalcinosis in these patients. However, whether arterial stiffness and vascular calcification are associated with the LVH in patients with ESRD has not been well established. Forty-nine patients on chronic hemodialysis participated in this study. 1) To better understand the mechanism underlying the increased incidence of LVH, we studied the relation between LVH and each of arterial wall stiffness, aortic calcification, and numerous clinical parameters in 49 patients on chronic hemodialysis. 2) To evaluate the contribution of arterial stiffness and arterial calcification to LVH in hemodialysis patients, we performed the present clinical analysis on 49 patients on chronic hemodialysis. We used an automatic device to measure arterial pulse wave velocity (PWV) as an index of arterial wall stiffness. The aortic calcification index (ACI) was quantified morphometrically by CT scan. The left ventricular mass index (LVMI) was estimated by M-mode echocardiography. To understand the mechanism underlying the increased incidence of LVH, we examined the factors contributing to LVMI in these patients. The correlation between each of the study parameters and LVMI as an indicator of LVH was then examined. The LVMI value was correlated positively with PWV (r=0.439, p=0.0014), systolic blood pressure (r=0.421, p=0.0023), and ACI (r=0.467, p=0.0006). A stepwise linear regression analysis showed that PWV, systolic blood pressure, and ACI were independently associated with LVH in our subjects. These results suggest that LVH is associated with hypertension, increased arterial stiffness, and the extent of vascular calcification in hemodialysis patients, with vascular calcification being the most important contributor to the development of LVH. Alteration of pulsatile dynamics contributes to an increase in left ventricular load and thus is also related to the LVH in these patients. These results suggest that LVH is associated with hypertension, increased arterial stiffness, and the extent of vascular calcification in hemodialysis patients. Vascular calcification, which alters the pulsatile dynamics and thereby contributes to an increase in left ventricular load, is the most important contributor to the development of LVH in patients undergoing hemodialysis.