Among the cardiac implantable electrical devices used in pediatric cardiology, a pacemaker (PM) is mainly used rather than an implantable cardioverter defibrillator (ICD) and cardiac resynchronization therapy (CRT). For pediatric patients without a congenital heart disease (CHD), epicardial leads are commonly used because of the small body size. The most common indication for using a PM is congenital complete atrioventricular block (CCAVB). ICD implantation in patients who weigh ＜30 kg, mainly those with long QT syndrome or hypertrophic cardiomyopathy, shock leads are required to be implanted in a different manner than those in other adults. CRT is assumed to be effective in patients with left ventricular conduction delay and dyssynchrony, chiefly in those with CCAVB or cardiomyopathy. For CHD patients, epicardial leads are selected for those with limited venous access to the heart or the intracardiac shunt. PM implantation is considered based on the anatomy, operative procedure, and hemodynamics. The PM timing needs to be set while assessing the hemodynamics because it has a considerable impact on the hemodynamics of CHD patients. The indication for the use of ICD for the primary prevention of sudden cardiac death in CHD has not been established yet owing to the heterogeneous cardiac anatomy and lack of randomized clinical trials. For CRT, the pacing lead positions should be decided according to the ventricular morphology and the patterns of ventricular dyssynchrony.