The aim of this study was to investigate the effectiveness of cognitive-behavioral therapy (CBT) on aggression in patients with thalassemia.Methods: This is an applied study in terms of objective and it is semi-experimental due to the nature of the subject, pre-test, post-test and follow-up conducted in the control group. The sample consisted of 30 patients with thalassemia city in Bojnourd, they were selected by convenience sampling method and voluntarily participated in the study. The participants were randomly divided into two groups. The first group received cognitive - behavioral therapy and the second group received no therapy. Both groups were assessed by the pre-test, post-test, and one month follow up. The assessment tool in this study were Aggression Questionnaire AGQ. Data were analyzed using SPSS software and variance analysis with repeated measures.Findings: the results showed that there is a significant correlation between the experimental group that received cognitive behavioral therapy and the control group that received no therapy in reducing aggression. These findings have important theoretical and clinical interventions.Conclusion: The results of this study will be to assess and validate detection and more precise controls used in the treatment of aggression in children with thalassemia in clinics. As well as services (CBT) to this group of clinical population as a nonpharmacologic (NMT) are effective.Keywords: cognitive behavioral group therapy, aggression, children with thalassemi
