WHAT IS ALREADY KNOWN ON THIS TOPIC: Application of continuous positive airway pressure (CPAP) for patients with acute respiratory distress reduces the need for tracheal intubation and mechanical ventilation. Case series have demonstrated CPAP's feasibility in out-of-hospital settings. WHAT QUESTION THIS STUDY ADDRESSED: Seventy-one out-of-hospital patients with severe respiratory distress, randomized to receive CPAP or usual care, were assessed to determine need for tracheal intubation and mortality. WHAT THIS STUDY ADDS TO OUR KNOWLEDGE: Within the CPAP group, the rate of intubation was 30% less than the usual care group, and mortality was 20% lower. HOW THIS MIGHT CHANGE CLINICAL PRACTICE: Emergency medical services systems and their medical directors should consider making CPAP available as part of the treatment for out-of-hospital severe respiratory distress patients, particularly in systems with long transport times.