Background. Cardiovascular complications are the most important cause of mortality in end stage renal disease. The aim of this study is to evaluate systolic and diastolic functions of children with chronic renal disease. Methods. Twenty-five children on renal replacement therapy (16 on peritoneal dialysis, 9 on hemodialysis), 10 children in chronic renal insufficiency group, and 27 healthy subjects were examined by echocardiography. Results. No significant difference was observed in systolic functions between patients and controls. Left ventricular mass index was significantly higher in hemodialysis and peritoneal dialysis patients when compared with controls, where no significant difference was determined between chronic renal insufficiency group and controls. Although left ventricular mass index was tended to be higher in hemodialysis than peritoneal dialysis group, this was not significant. Peak late diastolic flow velocity (A) was significantly higher in dialysis groups when compared to controls. E/A ratios were significantly lower in dialysis groups than controls. Conclusion. The finding that the diastolic functions were impaired in both children on peritoneal dialysis and hemodialysis suggests that peritoneal dialysis is not superior to hemodialysis for preserving diastolic cardiac functions. Further studies with larger patient groups are needed to show long-term effects of peritoneal dialysis and hemodialysis on cardiac functions.