We describe polygraphic respiratory alterations during sleep in a child with neurofibromatosis. The patient, a four-year-old boy, had a medical history of neurofibromatosis and recurrent acute respiratory failure responsive to mechanical ventilation. All-night polysomnography showed severe nocturnal hypoventilation with marked hypercapnia (TcPaCO2 70 mmHg) and hypoxemia (SaO2 less than 40%). Nocturnal hypoxemia and hypercapnia and depressed response to the hyperoxic hypercapnic test confirmed the diagnosis of central hypoventilation syndrome. Cerebral magnetic resonance imaging disclosed lucent areas in the globus pallidus, mesencephalus and left upper pons. Therapy with nocturnal nasal positive bilevel ventilation reversed nocturnal hypoxemia and hypercapnia. This study suggests that patients with neurofibromatosis should be investigated for concomitant severe hypoventilation, particularly when clinical symptoms suggest brain stem lesions.