Five patients with chronic respiratory failure from neuromuscular disease and symptomatic worsening nocturnal hypoventilation were treated with nocturnal ventilation. Home ventilation at night was provided by a volume-cycled positive pressure ventilator attached to a nasal mask originally designed to administer nasal continuous positive airway pressure (CPAP) for obstructive sleep apnea. The device was well tolerated. Symptoms of headache, insomnia/somnolence, and impaired intellectual capacity rapidly disappeared with nocturnal ventilatory support. Daytime arterial PO2 and PCO2 improved after therapy. There are several advantages over commonly used, negative pressure devices for nocturnal ventilation. These include patient synchronization of tidal volume, ease of application, less cumbersome apparatus, more nocturnal patient mobility, and absence of production of upper airway obstruction.