The use of implantable cardioverter defibrillators in children presents several unique challenges for the pediatric cardiologist. Size considerations and hardware limitations are important in the current generation of devices that are not designed with children in mind. Defibrillator devices are used to prolong life, which may have significant implications for leads and electrodes that are affixed to the heart in a child who has continued growth potential. A greater number of children with congenital heart defects are surviving into adulthood, many of whom have a risk of late sudden death following repair. These patients may also have unique anatomic considerations that may affect device placement. This article will address some of the issues faced when considering the use of implantable-defibrillator therapy in the pediatric population.