Noninvasive face mask ventilation has been used successfully in patients with paralytic respiratory failure. This study evaluated whether noninvasive face mask ventilation can be used for patients with acute respiratory failure due to intrinsic lung disease. Six patients with hypercapnia and four with hypoxemic acute respiratory failure met clinical and objective criteria for mechanical ventilation, which was delivered with pressure control and pressure support via a tightly strapped, clear face mask. No patient terminated the study because of inability to deliver adequate ventilation or to improve oxygen exchange; three eventually required endotracheal intubation. The mask was generally well tolerated. All patients had a nasogastric tube placed on suction, and none vomited or aspirated. The mean duration of treatment was 33 h (range, 3 to 88). The physiologic response was considered similar to that which would have been achieved with conventionally delivered ventilation. Noninvasive face mask ventilation may have a role in managing respiratory failure.