A patient with Hunter syndrome and diffuse airway obstruction had daytime hypersomnolence, snoring, and alveolar hypoventilation. Polysomnography showed severe obstructive sleep apnea. In the past, all reported cases of sleep apnea in patients with mucopolysaccharidoses had been treated with tonsillectomy/adenoidectomy or tracheostomy. This patient, in whom tracheostomy would have been very difficult due to the diffuse nature of his airway involvement, was successfully treated with high pressure nasal CPAP and supplemental oxygen.