OBJECTIVE:: To report the utility of inhaled nitric oxide to ameliorate excessive hypoxemia in children with pulmonary arteriovenous malformations after the Fontan procedure. DESIGN:: Case series. SETTING:: A tertiary pediatric cardiac intensive care unit in a freestanding children's hospital. PATIENTS:: Three children with complex congenital heart disease and pulmonary arteriovenous malformations who underwent the Fontan procedure. INTERVENTIONS:: The 3 patients all exhibited moderate-to-severe hypoxemia in the immediate postoperative period. The hypoxemia persisted despite mechanical ventilation and oxygen at an Fio2 of 1.0. Inhaled nitric oxide was initiated with immediate and dramatic improvements in oxygen saturation in all patients. All patients were eventually weaned off inhaled nitric oxide. CONCLUSIONS:: The use of inhaled nitric oxide in patients with pulmonary arteriovenous malformations after having the Fontan procedure improves hypoxemia and may potentially reduce postoperative morbidity, unnecessary testing, and duration of hospital stay. Copyright © 2011 by the Society of Critical Care Medicine and the World Federation of Pediatric Intensive and Critical Care Societies.