Endotracheal intubation consists on placing a tube in the trachea either through the mouth (orotracheal intubation) or through the nose (nasotracheal intubation). Although maintaining the airway patent and providing adequate ventilation are not synonymous with intubation, this procedure provides a closed ventilation system while ensuring patency and protecting the airway. Intubation is fairly safe in oxygenated and physiologically stable patients but it is not free from serious complication and consequently it should always be considered as a dangerous technique, especially in critically-ill patients. In addition, given that the anatomy of the airway in children differs according to age, the techniques used to intubate show considerable variations. For all these reasons and despite the often urgent nature of airway problems in children, the placement of an endotracheal tube must be approached in a deliberate and calm manner if trauma to the airway and patient instability are to be avoided. Thus, whenever circumstances permit, intubation should be carefully prepared with assessment of factors that might cause problems such as the indication for intubation, possible airway abnormalities, risk of aspiration, and hemodynamic, respiratory and neurological status. Such and evaluation allows the most appropriate intubation technique to be chosen.