Sudden cardiac death (SCD) in children is the result of multiple etiologies and treatment (prophylaxis) must be tailored accordingly. In children who do not have congenital heart disease, surgical therapy of SCD typically consists of implantation of an internal defibrillator, with specific attention to the small size of the patient. In children who have unrepaired congenital heart disease, therapy of SCD is primarily repair of the congenital anomaly. In children or young adults who have previously undergone surgery for congenital heart disease, SCD therapy consists of repair of any residual or acquired structural defect, often in combination with antiarrhythmia surgery or defibrillator implantation.