Thalassemia is a genetic disease of autosomal recessive inheritance, characterized by the reduction or absence of production of one of the normal globin chains, which causes chronic hemolytic anemia. Iron overload is the main prognostic factor for mortality and morbidity, and the quality of chelation remains the major prognostic factor for the disease. The aim of our work is to emphasize the major impact of chelating treatment in post-transfusion hemochromatosis, on life expectancy, the prevention of cardiac, hepatic and endocrine complications. Our study is a cross-sectional study on 15 cases of major β thalassemia in children in the pediatric hematology unit of the CHU Oujda whose current age is between 2 and 13 years with an average of 8 years old and predominantly female (66%). Therapeutically, all our patients are on a transfusion program every 2 to 4 weeks. The iron overload assessment in our series was based on the 3-month ferritinemia assay, liver MRI, and annual echocardiography. In our series, 14 of our patients were put on iron chelating treatment for which Deferasirox was the molecule of choice. All of our patients tolerated Deferasirox very well and did not tolerate Deferriprone. The evolution was marked by the improvement of ferritin in 7 cases, 4kept stationary ferritinemia and 3 cases increased their ferritinemia level. In the light of these results, thalassemia is a real public health problem whose complications are serious and whose morbidity and mortality are high, hence the need for good management for a good prognosis based on the 2 pillars monthly transfusion and iron chelation. Hematopoietic stem cell transplantation remains the only curative treatment.