Data concerning electrocardiographic (ECG) abnormalities in thalassemic cardiomyopathy are scanty. Current techniques to detect early findings of myocardial involvement in thalassemia (Magnetic Resonance, Stress Echo, Tissue Doppler Imaging) are not widely available. We sought to determine whether new ECG abnormalities emerge in thalassemia patients when heart failure due to cardiomyopathy occurs. ECG and Echo Doppler examinations of 28 consecutive adult thalassemia patients with heart failure observed at our hospital were compared with ECG and Echo Doppler examinations performed before the onset of heart dysfunction and with those of 60 age and sex-matched patients with thalassemia without evidence of cardiac involvement. All the patients with heart failure had new ECG abnormalities. New onset supraventricular arrhythmias, T wave inversion, low voltages, right QRS axis deviation and S1Q3 pattern developed respectively in 46%, 79%, 43%, 18% and 15% of thalassemic patients with heart failure. None of the patients without heart failure showed any ECG abnormality (P < 0.001). In conclusion this study suggests that new onset ECG abnormalities are always evident in patients with and always absent in patients without heart failure due to thalassemic cardiomyopathy.