Ventricular fibrillation is an infrequent arrhythmia in cardiac arrest occurring in the out-of-hospital setting in infants and small children. However, outcome is good provided early defibrillation is performed; consequently, this procedure is one of the main links in the chain of survival in children with a shockable rhythm. Automated external defibrillators are small devices that can analyze heart rhythm and deliver a dose of electric energy when considered timely by the operator. Automated external defibrillators are easy to use and can be operated, if necessary, by anyone. Therefore, all pediatricians should be aware of how these devices work and be able to use them safely and effectively, following the current defibrillation protocol.