The signal-averaged electrocardiogram (SAECG) facilitates noninvasive recording of low-amplitude cardiac signals such as ventricular late potentials. The SAECG has been used to predict life-threatening ventricular tachyarrhythmias in patients after acute myocardial infarction and with nonischemic dilated cardiomyopathy and to screen for inducible ventricular tachycardia in patients with unexplained syncope and with non-sustained ventricular tachycardia. This technical information report focuses on currently accepted methodology and clinical applications of the SAECG.