The obstructive sleep apnea syndrome (OSAS), is a common cause of morbidity during childhood. Childhood OSAS usually stems from adenotonsillar hypertrophy. OSAS in infants is usually related to craniofacial anomalies. Other risk factors include obesity and neuromuscular disease. Symptoms include snoring and difficult breathing during sleep. Infants may have problems with feedings and experience failure to thrive. 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.