Background In thalassemia major (TM) patients, major mortality is due to cardiac hemosiderosis. Several types of iron chelating agent available recently are given to overcome this problem Objective ro compare cardiac dysfunction in thalassemia major patients who used subcutaneous deferoxamine (DFO) to those who used oral deferiprone (DPP) as an iron-chelating agent. Methods This cross-sectional study was held at the Thalassemia Center, Department of Child Health-Cipto Mangunkusumo Hospital (DCH-CMH), Jakarta. We included TM patients aged 10-18 years with a mean pre-transfused hemoglobin level of >= 7 g/dL in the prior year, and who had used DFO or DPP for at least 1 year with good compliance, at a standard dose of DFO at 40-60 mg/kg/day for 5 days a week or DPP at 50-100 mg/kg/day. We excluded TM patients with congenital heart disease or overt heart failure. Trans-thoracal echocardiography was performed at the Integrated Cardiac Service, CMH by a pediatric cardiologist using the conventional method and tissue Doppler imaging (11)1) consecutively, and within 2 weeks of the subject's receiving a packed red blood cell (PRBC) transfusion. The 57 TM subjects consisted of 19 DFO users and 38 DFP users. Results In our subjects, diastolic dysfunction was more commonly seen than systolic dysfunction, especially moderate diastolic dysfunction. In the DFO group, diastolic dysfunction only was detected in 3/19 subjects, systolic dysfunction only in 1/19 subjects, and both diastolic and systolic dysfunction in 1539 subjects. None of the DFO users had normal cardiac function. In the DPP group, diastolic dysfunction only was seen in 6/38 subjects, and both diastolic and systolic dysfunction in 30/38 subjects, while 2/38 subjects had normal cardiac function. Conclusion Diastolic and/or systolic dysfunction was detected in the majority of subjects, but with preserved global cardiac function. We found that cardiac dysfunction was not significantly different in the two iron chelator groups. For all subjects, diastolic dysfunction was seen in 89% of cases, while systolic dysfunction was detected in 77% of cases.