The signal-averaged electrocardiogram (SAECG) facilitates noninvasive recording of low-amplitudecardiac signals such as ventricular late potentials. The SAECG has been used to predict life-threateningventricular tachyarrhythmias in patients after acute myocardial infarction and withnonischemic dilated cardiomyopathy and to screen for inducible ventricular tachycardia in patients withunexplained syncope and with nonsustained ventricular tachycardia. This technical information reportfocuses on currently accepted methodology and clinical applications of the SAECG.