Endothelial dysfunction was reported to be present in pediatric of chronic renal failure (CRF), we aimed to assess endothelial function non invasively in pediatric patients with CRF, the study included 34 cases of CRF compared with 30 healthy control, we measure endothelial dependent vasodilatation and endothelial independent vasodilatation of the brachial artery using Doppler, we found that endothelial function was impaired in 71% (24 cases) of our cases with no significant correlation with hypertension or golmerular filteration rate or the disease duration.