A battle casualty is any casualty incurred in action. "In action" characterizes the casualty status as having been the direct result of hostile action, sustained in or relating to combat, or sustained going to or returning from a combat mission provided that the occurrence was directly related to hostile action.

People killed or wounded mistakenly or accidentally by friendly fire directed at a hostile force or what is thought to be a hostile force are considered battle casualties. However, injuries due to the elements, self-inflicted wounds, and, except in unusual cases, wounds or death inflicted by a friendly force while the individual is in absent-without-leave or dropped-from- rolls status, or is voluntarily absent from a place of duty are not to be considered as sustained in action and thereby not to be interpreted as battle casualties.