To evaluate the reliability of the echocardiographic examination in assessment of adult patient with thalassemia major, in comparison with clinical, electrocardiographic and/or chest x ray exams, 103 patients with thalassemia major, mean age 20 years (range 14 to 30 years), were studied and compared with 30 age matched normal subjects. All patients were receiving transfusions regularly to maintain hemoglobin levels above 11 g/dl and subcutaneous infusions of desferrioxamine (about 40 mg/kg/day) to reduce hemosiderosis. The patients were divided into three groups according to their cardiac impairment, deduced by clinical history, electrocardiography (ECG) and/or chest x ray. Group I (36 patients) showed no signs or symptoms of cardiac impairment. Group II (38 patients) had only signs of cardiac impairment by ECG and/or chest x ray. Group III (29 patients) had both symptoms and signs of cardiac failure. In comparison to normal controls, Group I showed an increase in left ventricular (LV) dimension (EDD) and mass (p < 0.001), Group II and III showed a decrease in LV fractional shortening (FS; p < 0.001) too. In comparison to Group I, Group II showed a decrease in LV FS (p < 0.05), Group III showed an increase in LV EDD and mass (p < 0.001) too. In comparison to Group II, Group III showed an increase in LV EDD and mass (p < 0.001), and a decrease in LV FS (p < 0.001). In conclusion, echocardiographic examination appears a tool more reliable than clinical, electrocardiographic and/or chest x ray examination in assessment of adult patient with thalassemia major.(ABSTRACT TRUNCATED AT 250 WORDS)