Pediatric thoracic emergencies are frequent and may be due to a large spectrum of lesions including traumatic and non traumatic pathologies, such as foreign bodies, mediastinal tumors, pulmonary infections, asthma, pneumothorax and delayed manifestations of congenital chest malformations. Emergencies require rapid diagnosis to make a treatment plan and in most cases, radiology plays an essential role. Plain chest radiographs remain the initial study with inspiratory films. In certain circumstances, the use of expiratory films is absolutely necessary. Ultrasonogragraphy is the primary modality for evaluation of pleural effusions. Computed tomography (CT), with volume acquisition and more rapid scanning, is a technique capable of imaging the lungs and mediastinum with excellent spatial resolution in the pediatric population. CT provides more information than chest radiographs. This explains the increasing indications of CT in the evaluation of pediatric thoracic emergencies, more particularly traumatic emergencies.