Atrioventricular (AV) block is a delay or an interruption in the transmission of an impulse from atria to ventricles due to an anatomic or a functional impairment in the conduction system. Atrioventricular block may be congenital or acquired. Electrocardiographic screening of asymptomatic school-aged children (median, 12.4 years) in Japan found the prevalence of a third-degree AV block to be 2 per 100,000. We report a case of asymptomatic complete AV block of unknown etiology in a 13-year-old child who did not require pacemaker placement. The importance of recognizing an asymptomatic complete AV block in the pediatric population, the classification and controversies of pacemaker placement, and the complications of pacemaker placement are discussed.