Background: Cardiovascular disease is an important cause of morbidity and mortality in patients undergoing maintenance dialysis. There is evidence supporting a direct role for the uremic milieu, and an indirect role as well, for enhanced cardiovascular complications. On-line dialysis modalities, such as on-line hemodiafiltration, raise particular concerns because not only small molecules are removed more effectively as compared to low-flux hemodialysis, but in addition, a considerable clearance of so-called middle molecular weight (MMW) substances is obtained including those involved in cardiovascular morbidities.Objectives: To assess the effect of on-line hemodiafiltration on removal of uremic toxins that cannot be removed during conventional hemodialysis, e.g. homocysteine, and improving the chronic inflammatory state associated with chronic kidney disease and the possible impact of these changes on myocardial function in chronic hemodialysis patients.Methods: In this study, we compared different clinical, lab and radiological data of 30 chronic hemodialysis pediatric patients on low-flux hemodialysis with the same data after 6 months of initiation of predilution on-line hemodiafiltration to clarify the possible impact of on-line hemodiafiltration on cardiovascular system in those patients.