Objective To investigate the effect of dialysate calcium concentration on the left ventricular(LV) structure and function of maintenance hemodialysis(HD) patients with end-stage renal disease(ESRD). Methods Fifteen HD treatments were applied respectively with dialysate Ca2+ concentrations of 1.25mmol/L(dCa2+1.25),1.5mmol/L(dCa2+1.5)and 1.75mmol/L (dCa2+ 1.75) in 30 ESRD patients. The LV structure and function were echocardiographically examined before and after the fifteenth HD session, respectively. Results Serum Ca2+ decreased significantly during the dCa2+1.25 HD(1.24±0.08 vs 1.16±0.07 mmol/L P＜0.05), serum Ca2+ increased significantly with the dCa2+1.5HD(1.22±0.07 vs. 1.28±0.08 mmol/L P＜0.05) and dCa2+1.75 HD(1.23±0.08 vs 1.32±0.09mmol/L P＜0.05), and plasma intact parathyroid hormone(iPTH) decreased significantly with the dCa2+1.5 HD(218±146vs.182±156ng/L P＜0.05) and dCa2+1.75 HD(215±157 vs 166±150ng/L P＜0.05). LV structure and systolic function were not altered during any of the treatments. The changes in E/Amax and isovolumic relaxation time IVRT suggested impairment of LV relaxation during HD in each session, but only with the dCa2+1.75 HD was the impairment statistically significant(E/Amax 1.27±0.31 vs. 0.92±0.32 P＜0.05; IVRT (133±27) vs (168±39)msecond, P＜0.05). The change in serum Ca2+ was the only variable correlating independently with the changes in E/Amax(r=-0.34，P＜0.05) and IVRT(r=0.28，P＜0.05). Conclusion The changes in dialysate calcium concentration affect serum Ca2+ directly. HD with different calcium concentration dialysate does not impair the LV structure and systolic function; HD with high-calcium dialysate impairs LV diastolic function when compared with lower calcium dialysate treatmemt.