BACKGROUND Children with congenital heart disease often experience respiratory symptoms in the preoperative and perioperative periods, which can complicate their management. An uncommon but important cause of respiratory insufficiency in such children is external airway compression. METHODS We operated on 5 patients (median age, 6 months) with significant respiratory distress attributable to compression of the central airways by a dilated ascending aorta before or after repair of concomitant cardiovascular defects. Four of these patients had right aortic arch and 3 had pulmonary atresia with a ventricular septal defect and major aortopulmonary collaterals. In all patients, aortopexy was performed at the time of operation for the cardiovascular defects (n = 3) or after symptoms developed in the postoperative period (n = 2). The 3 patients in whom airway compression produced symptoms preoperatively also underwent reduction ascending aortoplasty. RESULTS Symptoms resolved immediately after operation in 3 patients, whereas symptoms persisted in the other 2 patients and tracheostomy was required. At follow-up of 20 months to 5 years, all patients are alive and well, with mild or moderate respiratory symptoms in the 2 patients who required tracheostomy, both of whom were decannulated within 13 months. CONCLUSIONS External airway compression can cause significant morbidity in patients with congenital heart defects other than vascular rings. In patients with respiratory symptoms in the context of a lesion that involves increased aortic outflow during intrauterine life and consequently, an enlarged ascending aorta, such as tetralogy of Fallot with pulmonary atresia, airway compression should be considered as a cause, especially if a right aortic arch is present or the patient also has pulmonary atresia with a ventricular septal defect and collaterals. Attempts to address this problem surgically may provide substantial relief, but increasing duration of airway compression is likely to lead to tracheal or bronchial malacia and persistent symptoms even after the compression is relieved.