The obstructive sleep apnea syndrome is a common cause of morbidity during childhood. Childhood obstructive sleep apnea syndrome is usually secondary to adenotonsillar hypertrophy. Other risk factors include craniofacial anomalies, obesity, and neuromuscular disease. Symptoms include snoring and difficulty breathing during sleep. Definitive diagnosis is made by polysomnography. Normative polysomnographic parameters vary with age; thus age-appropriate norms must be used. In contrast to adults, children often manifest a pattern of persistent partial airway obstruction during sleep, rather than cyclical, discrete obstructive apneas. Most children are cured by tonsillectomy and adenoidectomy. However, some children require further therapy, such as continuous positive airway pressure.