Electrocardiography was performed in a newborn boy without organic heart disease, in whom supraventricular extrasystoles with varying coupling were seen. The supraventricular extrasystoles were occasionally followed by ventricular extrasystoles. The coupling intervals of ventricular extrasystoles to the preceding supraventricular extrasystoles were also considerably variable. Ventricular tachycardia occurred following comparatively late coupled ventricular extrasystoles. This is the first known report on ventricular tachycardia following comparatively late coupled ventricular extrasystoles in a newborn infant. This strengthens our previous suggestion that such ventricular tachycardia can be caused by longitudinal dissociation in the reentrant pathway of extrasystoles.