Twenty-two infants and children were found to have clinically significant obstructive sleep apnea. A history suggesting complete or partial airway obstruction during sleep was obtained on all patients, and physical examination of the sleeping patient revealed snoring, retractions, or OSA in 21 patients. Nevertheless, the mean delay in referral for 20 patients first seen after the neonatal period was 23 +15 (+ SD) months. Sixteen of 22 patients (73%) developed serious sequelae: cor pulmonale in 12 (55%), failure to thrive in six (27%), permanent neurologic damage in two (9%), and behavioral disturbances, hypersomnolence, or developmental delays in five (23%). Clinical and radiologic evaluations revealed anatomic abnormalities which narrowed the upper airway in 21 patients; enlarged tonsils and/or adenoids in 14, micrognathia in three,generalized facial abnormalities in three, and cleft palate repair/tonsillar hypertrophy in one. In five patients, upper airway fluoroscopy was performed and was helpful in establishing the site and mechanism of obstruction. Polygraphic monitoring was utilized to quantify the frequency and duration of OSA. Prolonged partial airway obstruction during sleep resulted in significant hypercarbia in 11 patients and hypoxemia in five. Twenty patients improved after surgery which relieved or bypassed the pharyngeal airway obstruction; two cases are pending. Increased awareness of OSA and examination of the sleeping patient should result in earlier treatment and less morbidity for infants and children with OSA.