Cardiac involvement related to iron overload caused by long-term blood transfusion is a major cause of death for patients with thalassemia major. Patients’ survival will be improved greatly if cardiomyopathy resulted from transfusional iron overload could be detected timely and effective iron chelation be initiated promptly. In the present article, various evaluation methods currently used in clinical practice are reviewed, with particular focus on cardiac MRI for the monitoring of myocardial involvement related to iron overload.