Military medicine has made numerous enduring contributions to the advancement of pulmonary medicine. Acute respiratory distress syndrome was first recognized as a complication in battlefield casualties in World War I and continued to play a significant role in the treatment of casualties through the Vietnam War. Innovative surgeons during World War II devised methods to assist their patients with positive pressure breathing. This concept was later adopted and applied to the development of mechanical ventilation in the late 1940s and early 1950s. The continued treatment of acute respiratory distress syndrome in combat casualties by military physicians has provided a major impetus for advances in modern mechanical ventilation and intensive care unit medicine.