For the past 4 decades, the prone position has been employed as an occasional rescue option for patients with severe hypoxemia unresponsive to conventional measures applied in the supine orientation. Proning offers a high likelihood of significantly improved arterial oxygenation to well selected patients, but until the results of a convincing randomized trial were published, its potential to reduce mortality risk remained in serious doubt. Proning does not benefit patients of all disease severities and stages but may be life-saving for others. Because it requires advanced nursing skills and escalation of monitoring surveillance to deploy safely, its place as an early stage standard of care depends on the definition of that label.