Fifty children and adolescents with obstructive sleep apnea syndrome and related breathing disorders during sleep are reviewed. Subjects were subdivided according to whether their breathing irregularity was secondary to a medical problem (group I) or was the primary complaint (group II). The most common presenting complaint was excessive daytime somnolence; hyperactivity and antisocial behavior also were cited frequently. In 20% of cases, substantial personality changes were reported. Clinical symptoms included failure to thrive, abnormal weight for age, acute cardiac or cardiorespiratory failure, hypertension, and frequent upper airway infections. Continuous, heavy snoring was reported in all cases; disrupted nocturnal sleep, sleep walking, nightmares, and enuresis were common. All subjects, and 22 control patients, were monitored polygraphically during sleep for at least one night. Nocturnal sleep in the reported population was severely disrupted. A complete disappearance of stage 3 NREM sleep was noted in 86% of cases; REM sleep was decreased less. The management of these cases is reviewed. Eight patients received permanent tracheostomies. Thirty children had tonsillectomy and/or adenoidectomy (three later required tracheostomy). Non-surgical approaches also were used, particularly in group 1. Follow-up on these cases to date is presented.