The aim of this work is to study the level of oxidative stress in blood of beta-thalassemia major patients with transfusional iron overload and chelation therapy as a central pathological process. Beta-thalassemia major results in an increase in the concentration of lipid peroxidation products in blood plasma of more than 100% and in the intensity of chemiluminescence - about 20% in comparison to healthy controls. The activity of the antioxidant enzyme superoxide dismutase in the blood of beta-thalassemia major patients is decreased by more than 30% and the total antioxidant activity is diminished by about 70% compared to controls. Experimental data confirm the progression of oxidative stress in patients with beta-thalassemia major: activation of free radical processes and lipid peroxidation, decreased antioxidant capacity. Strong oxidative damage and essential alternations define these parameters as sensitive markers of oxidative stress in patients with beta-thalassemia major. The combination of effective iron-chelatory agents with natural or synthetic antioxidants can be extremely helpful in clinical practice in the regulation of the antioxidant status of patients with beta-thalassemia major.