Emergencies always require rapid diagnosis and an urgent or semi-urgent medical, interventional, or surgical action. In most cases radiology plays an essential role in making an accurate diagnosis. Reviewing the causes of acute respiratory pathology in the different pediatric age groups, we thought it would be interesting to divide the pathologies into two main parts: one part concerning pathologies involving the air flow and the other part concerning pathology affecting the pulmonary parenchyma. We acknowledge, however, that both conditions can occur concomitantly. The esophagus is another anatomic structure in the thorax that can be responsible for acute pathology in children. Acute pathology predominantly involving the air flow can be intrinsic and/or extrinsic, affecting the upper airways, trachea, main and segmental bronchi, and the small airways. Acute lung pathology can be congenital, infectious, or less frequently, tumoral or traumatic in children. Pleural pathology and cardiogenic emergencies are discussed also. Acute esophageal pathology is discussed briefly.