Battle injuries sustained in conventional warfare are more likely to be lethal than are injuries sustained by civilians. Depending on the tactical situation, mortality may range from 20% to more than 80% of all casualties. The American experience indicates that about 90% of the total mortality occurs on the battlefield. Such casualties, those classified as killed in action, die before reaching medical care. More than 90% of all battle injuries (morbidity) are caused by penetrating missiles. Exsanguination from wounds of the heart/great vessels and penetrating/perforating wounds of the skull cause the majority of battlefield deaths. The frequency distribution of injury severity appears to be bimodal. A large peak occurs at low injury severity and indicates a population of casualties with relatively benign soft tissue wounds. A smaller peak at high injury severity represents those killed in action.