Patients who are diagnosed with acute lung injury/acute respiratory distress syndrome (ALI/ARDS) usually have ventilation-perfusion mismatch, severe decrease in lung capacity, and gas exchange abnormalities. Health care workers have implemented various strategies in an attempt to compensate for these pathological alterations. By rotating patients with ALI/ARDS between the supine and prone position, it is possible to achieve a significant improvement in PaO2/FiO2, decrease shunting and therefore improve oxygenation without use of expensive, invasive and experimental procedures. Prone positioning is a safe and effective way to improve ventilation when conventional strategies fail to initiate a patient response. Because a specific cure for ARDS is not available, the goal is to support the patients with therapies that cause the least amount of injury while the lungs have an opportunity to heal. Based on current data, a trial of prone positioning ventilation should be offered to the patients who have ALI/ARDS in the early course of the disease. Published studies exhibit substantial heterogeneity in clinical results, suggesting that an adequately sized study optimizing the duration of proning ventilation strategy is warranted to enable definitive conclusions to be drawn.