Obstruction is the most common manifestation of airway pathology by children. The practitioner may be confronted to this relatively frequent problem. The pathology spectrum is very wide, and includes congenital malformations, infections, traumas, and tumours. The most frequent etiology of congenital upper airway obstruction is laryngomalacia. Adenotonsillar hypertrophy is by far the most common cause of obstruction by children aged 2 - 7 years. The medical history and the clinical examination allow to determine the degree of emergency, to orientate the diagnosis, and to decide when to refer the patient to a specialist. Endoscopy is the gold standard examination for diagnosis. In some cases, others investigations, such as radiological examinations, may be necessary.