Hyperhomocysteinemia is a putative risk factor for cardiovascular disease in the hemodialysis population. Modifications of the dialysis regimen may result in a better removal of Hcy. We examined the effect of dialyzer membrane pore size on Hcy levels in pediatric hemodialysis patients. The study included twenty patients with ESRD on regular hemodialysis with the mean age (±SD) of 11±2.56 years. Plasma Hcy before and after dialysis were measured both on low-flux dialysis and 12 weeks after conversion to high-flux membranes. Despite the absence of significant reduction in predialysis homocysteine levels , high-flux dialysis was associated with improvement in important cardiovascular risk factors including anemia , hypertension and hyperphosphatemia.