We assessed the prevalence of electrocardiographic abnormalities in patients with systemic sclerosis and evaluated their functional significance through a comparison with echocardiographic findings. Seventy-two patients with systemic sclerosis and 64 controls underwent resting electrocardiogram (ECG) and M-mode, two-dimensional, Doppler and color Doppler echocardiography. Electrocardiographic abnormalities were observed in 48.7% of patients. Conduction disturbances (27.7%) infarction pattern (13.8%), non-specific ST-T wave changes (13.8%) and right ventricular hypertrophy (11.1%) were the most frequent abnormalities. QTc interval was significantly longer in patients with systemic sclerosis than in controls. Significant differences between patients and controls were found in the prevalence of long QTc interval (p = 0.0016) infarction pattern (p = 0.0016), right ventricular hypertrophy (p = 0.007) and non-specific ST-T wave abnormalities (p = 0.0016). All patients with infarction pattern and 90% of patients with prolonged QTc interval had some echocardiographic abnormalities. Electrocardiographic signs of right ventricular hypertrophy were 16% sensitive and 93% specific for pulmonary hypertension; the sensitivity and specificity of the combination of right ventricular hypertrophy, right atrial enlargement and right bundle branch block were 35% and 90%, respectively. Standard ECG is useful to assess cardiac involvement in patients with systemic sclerosis. If infarction pattern, right ventricular hypertrophy or long QTc interval are present, a cardiac involvement is very likely.