Indications for the use of therapy with continuous positive airway pressure (CPAP) in spontaneously breathing patients are increasing in number. The value of this technique without tracheal intubation was investigated in 14 patients with acute respiratory distress. In most patients (eight patients, or 57 percent) the technique was successful, as evidenced by avoidance of the necessity for tracheal intubation and improvements in clinical appearance, arterial oxygen pressure, and chest x-ray films. Complications were observed in three patients, but these necessitated discontinuation of therapy in only one. The use of this technique allows avoidance of endotracheal intubation and mechanical ventilation, with their attendant risks.