Oxygen use in prehospital care is aimed at treating or preventing hypoxemia. However, excess oxygen delivery has important consequences in select patients, and hyperoxia can adversely impact outcome. The unique environment of prehospital care poses logistical and educational challenges. Oxygen therapy in prehospital care should be provided to patients with hypoxemia and titrated to achieve normoxemia. Changes to the current practice of oxygen delivery in prehospital care are needed.