This study is planned, as there are contrasting reports on the oxidative status of hemodialysis (HD) patients. The aim of this work is to explore the oxidative stress in the HD population and give more explanation about their oxidative status. The main objectives are, first, to assess the role of Maleic dialdehyde (MDA), Nitric oxide (NO) as oxidative biomarkers, Glutatione peroxidase (GSH-PX) and Superoxide dismutase (SOD) as antioxidative biomakers. Second, to find the best biomarker that can correlate with the dialytic age of patients. Third, to determine the effect of oral iron therapy and the type of dialysis membrane used on the oxidative status. And, finally, to provide a reference for further research.Methods: Four widely used Biomarkers of oxidative stress: MDA and NO levels,SOD and GSH-Px activities were studied to accomplish the present work. The spectrophotometric method at different wavelengths was used. General blood chemistry including: total proteins, albumin, urea,creatinine, uric acid, triglycerides, total cholesterol, LDL-c and HDL-c were determined on Olympus AU 5400 Autoanalyzer.Results: 1- General blood chemistry: HD patients exhibit lower level of total proteins and albumin compared to the controls, these levels show a significant increase after the dialysis session. Significant differences were also observed for urea, creatinine and uric acid, which were higher in HD patients, compared to the controls and decrease significantly after the HD session. For the lipid profile, the total cholesterol and LDL- cholesterol were higher in the HD population than in the controls but no significant difference was found for triglyceride (TG) and HDL-cholesterol 2-oxidative status: MDA levels were significantly higher in HD patients than in the controls but no significant difference was found between the pre-HD and post-HD levels. SOD and NO exhibit a significant increase in HD patients than in the controls, after HD session SOD show a further increase while NO shows a significant decrease. GSH-Px activity was significantly decreased in HD patients and increased after the HD session but remained lower than in the controls. Among the biomarkers analyzed, only GSH-Px has presented a significant negative correlation with the duration of HD. Patients who were on a longer period of HD have the lower activity of the enzyme GSH-Px. No correlation was found between HD time and SOD activity, NO and MDA levels. None of the previous parameters has presented a significant correlation when the patients age increases. No significant difference regarding the parameters of oxidative stress was found between the patients who were taking iron therapy and those who did not take it. No difference in oxidative status was also found between the patients who used HE 1400 dialysis membrane and those who used F60 dialysis membrane.Conclusion: It is important to respect an efficient dialysis program of at least 3 times per week in order to avoid high levels of uremia an consequently avoid uremic complications. HD, despite being salvage way for end stage renal diseases (ESRD) patient, it is a source of oxidative stress responsible for the majority of complications developed by them. MDA is a reliable biomarker to assess the occurrence of oxidative stress in HD population, but it is not the suitable oxidative biomarker when assessing what is the effect of one HD session on the oxidative status because it is diffusible through the dialysis membrane. GSH-Px seems to be a suitable biomarker to monitor oxidative stress in HD population, it correlates with the HD duration, patients who are on a longer HD period have the lower enzyme activity, but it is more efficient when it is associated with Selenium and hydrogen peroxide determination.Furthermore, the measure of GSH-Px activity gives more detailed information if it is done at closed intervals over the dialysis session. From the principle of action of SOD and GSH-Px, we conclude that the hydrogen peroxide which is the final product of SOD is, at the same time, a substrate for GSH-Px. The determination of one requires automatically the determination of the other to give better knowledge about the oxidative status.The HD duration is a more eminent factor than the patients age in the oxidative status changes. The oral iron therapy does not influence the oxidative status compared to patients who were free from iron intake. The emergency use of highly biocompatible membrane with routinely use of insufficiently biocompatible membrane provides no positive effect to the patient. Correction of hypoproteinemia may help to improve the oxidative stress in HD patients.