A case of cardiac arrest in a ten year old child that was successfully resuscitated is here presented. The etiological investigation showed an Hypertrophic Cardiomyopathy (HCM). An Implantable Cardioverter Defibrillator (ICD) was placed for secondary profilaxy of Sudden Death (SD). Sudden Death in paediatric age is a rare accident with bad prognosis (survival with no sequel inferior to 5%) and with huge social impact. Hypertrophic Cardiomyopathy is a recognised cause of Sudden Death where prevention is possible. This report is important to enhance the question about the need and form of strategies to prevent sudden death of cardiac origin in pediatric age.