Low-amplitude late potentials detected in the terminal part of ventricular activation have been evaluated as a possible means of identifying patients prone to sustained ventricular tachyarrhythmias. These signals are usually absent in those without such arrhythmias and in normal subjects. 67 healthy subjects, with no suggestion of cardiac disease from examination or electrocardiograms, were studied in an effort to report the incidence of late potentials in normal subjects. Three subjects met the criteria for abnormal late potentials (4%); the vectormagnitude complexes of these subjects were indistinguishable from those seen in patients with spontaneous sustained ventricular tachycardia after myocardial infarction. Measured indices from our subjects were compared with those of normal subjects studied by other investigators utilizing similar analytic techniques and similar software and equipment. Explanations are considered for the occurrence of false-positives. It is concluded that the incidence of late potentials in normal subjects is very low and thought to represent some type of false-positive expression related either to the recording or analytic technique. However, in certain instances, the occurrence of late potentials in a seemingly normal person may be a predictor of underlying structural pathology.