To gradually improve the safety andeffectiveness in the clinical blood transfusion, especially in terms of immune harmony between units of blood transfused and the patient is essential. During treatment, patients with thalassemia is a group of patients with multiple blood transfusions abd the authors conduct study to found abnormal antibody system in patients with thalassemia erythrocytes in the Central Hospital of Thai Nguyen in 2011. Objective: Determine the rate of abnormal antibodies and some related factors in patients with thalassemia blood several times. Subjects: 112 patients with thalassemia from a blood transfusion. Method: descriptive cross-sectional, with a convenience sample. Results: The rate in thalassemia abnormal antibody transfusion was 30.35 percent,. Percentage of antibodies related to abnormal number of blood transfusions.