Objective: described the heart complications in patients with thalassemia major at Children's Hospital No.1 at Ho Chi Minh city. Methods: The authors described heart complications in 62 thalassemia major patients at Children's Hospital No1 from February 2011 to August 2011 (age under 15 years old). All patients were taken medical history, physical examination, checked complete blood count, ferritin, ECG, chest X-ray, and Doppler Echocardiography. Results: Heart complication was recorded in 83.9 percent, including 77.4 percent heart dilation, 24.2 percent pulmonary hypertension, 17.7 percent left ventricular hypertrophy, 12.9 percent congestive heart failure. Heart failure and pulmonary hypertension were coexisting. Patients with heart complication were younger, started earlier and transfused earlier than patients without heart complication. Heart complication patients had severe anemia and iron overload than other groups however there was smaller rate of chealation and transfusion in this group. Conclusion: the proportion of heart complication in patients with thalassemia major was high. There were various types of complication however they could appear at the same time.