Noncardiogenic pulmonary edema can be fatal without adequate resuscitation. We report, for the first time, the use of prone positioning in the immediate post-cardiac surgical period to treat a patient with profound hypoxemia secondary to massive (noncardiogenic) pulmonary edema. Prone positioning corrects ventilation-perfusion mismatch and allows gravity-dependent drainage of capillary leak-mediated endobronchial pulmonary fluid.