Background: Anemia develops early in the course of renal failure, becomes prominent as the disease progresses, and contributes substantially to disability. The availability of recombinant human erythropoietin (rHuEPO) has led to the almost complete disappearance of the severe anemia of end stage renal disease. Objectives: The aim of this work is detection of anti-EPO antibodies in pediatric hemodialysis (HD) patients under EPO therapy and its relation to type, dose and duration of therapy. Methods: Our subjects were divided into two groups: Group (1) included randomly selected HD pateints from the Pediatric Dialysis Unit, Children′s Hospital, Ain Shams University. Their ages ranged from 8-22 years (mean 14.83 ± 3.4 years). Twenty-five were females and thirty-four were males. Their duration of illness ranged from 1 month to 12 years (mean 3.9 ± 3 years). Twelve patients were receiving regular injections of EPO β and 47 were receiving EPO α. Group (2) included healthy subjects age and sex matched with group (1) as control group. In addition to clinical evaluation, venous samples were collected from the patients before dialysis session and examined for the presence of anti-EPO antibodies using elsia method. Complete blood account on T-540 cell counter was also done for all patients. Results: In our results we found positive anti-EPO antibodies in 44.1% of our subjects. In patients with positive antibodies the blood indices for anemia were significantly lower than in patients with negative antibodies.  Also antibodies were positive in 48.9% and 25% of patients receiving EPO α and EPO β respectively. No relationship could be detected between the presence of anti-EPO antibodies and factors affecting the efficiency of dialysis (duration of dialysis, length of dialysis session, dialyzer surface area). Not a single patients with positive anti-EPO antibodies had a Hb concentration equal to or more than the target value in renal failure patients (11 g/dL) while in patients with negative anti-EPO antibodies only one patient (3%) did not reach the target Hb level. Conclusions: Anti-EPO antibodies were found in 44.1% of our sample of HD patients. The prevalence of antibodies was more in patients receiving EPO α than EPO β. No relationship could be found between factors affecting the efficiency of dialysis and the presence of anti-EPO antibodies. We could not find a relation between dose and duration of EPO therapy and the development of such antibodies. Our patients did not show any of the features suspicious of pure red cell aplasia.