This report is written in response to numerous requests for war casualty statistics and lists of war dead. It provides tables, compiled by sources at the Department of Defense, indicating the number of casualties among American military personnel serving in principal wars and combat actions.Wars covered include the Revolutionary War, the War of 1812, the Mexican War, the Civil War, the Spanish-American War, World War I , World War II , the Korean War , the Vietnam Conflict , and the Persian Gulf War . Military operations covered include the Iranian Hostage Rescue Mission , Lebanon Peacekeeping , Urgent Fury in Grenada , Just Cause in Panama , Desert Shield and Desert Storm , Restore Hope in Somalia , Uphold Democracy in Haiti, and the ongoing Operation Enduring Freedom and Operation Iraqi Freedom .For the more recent conflicts, starting with the Korean War, more detailed information on types of casualties, and when available, demographics have been included. This report also cites sources of published lists of military personnel killed in principal wars and combat actions. This report will be updated as events warrant. A review of the composite data reveals the following. During the period between the Revolutionary War and the Persian Gulf War, it was the Civil War that produced the most American fatalities, when Union statistics and Confederate estimates are taken into account. World War II was the first war in which there were more battle deaths than deaths from other causes such as accidents, disease, and infections. With a total of 382 in-theater deaths, 147 of which were battle deaths, the Persian Gulf War was the least costly in terms of fatalities (see Table 1 ). The ongoing Operation Iraqi Freedom to date has produced more than four times the number of in-theater deaths than the Persian Gulf War (which lasted seven months). The casualty statistics for wars long ended are updated periodically, sometimes yearly. This almost always reflects the identification of remains of persons previously listed as missing in action and those persons’ reclassification as dead. Other reasons, much rarer, include the discovery of errors in casualty records for individuals or categories of people.