Advances in trauma care have accelerated over the past decade, spurred by the significant burden of injury from the wars in Afghanistan and Iraq. Between 2005 and 2013, the case fatality rate for United States service members injured in Afghanistan decreased by nearly 50 percent, despite an increase in the severity of injury among U.S. troops during the same period of time. But as the war in Afghanistan ends, knowledge and advances in trauma care developed by the Department of Defense (DoD) over the past decade from experiences in Afghanistan and Iraq may be lost. This would have implications for the quality of trauma care both within the DoD and in the civilian setting, where adoption of military advances in trauma care has become increasingly common and necessary to improve the response to multiple civilian casualty events. Intentional steps to codify and harvest the lessons learned within the military's trauma system are needed to ensure a ready military medical force for future combat and to prevent death from survivable injuries in both military and civilian systems. This will require partnership across military and civilian sectors and a sustained commitment from trauma system leaders at all levels to assure that the necessary knowledge and tools are not lost. A National Trauma Care System defines the components of a learning health system necessary to enable continued improvement in trauma care in both the civilian and the military sectors. This report provides recommendations to ensure that lessons learned over the past decade from the military's experiences in Afghanistan and Iraq are sustained and built upon for future combat operations and translated into the U.S. civilian system.