The United States undertook an extensive mobilization of military forces in Southwest Asia after the invasion of Kuwait by Iraq in August 1990. With this massive buildup and the short duration of the Persian Gulf War, an epidemiological comparison of military casualties was of interest. Information extracted from the Worldwide Casualty System maintained by the Department of Defense was used to describe the casualties. Of the 219 (212 men and 7 women) US casualties, 154 were killed in battle and 65 died from nonbattle causes. Thirty-five of the battle deaths were a result of friendly fire. Eighty-three percent of all casualties were white and the mean age at death for all casualties was 26.9 years. The Army had the highest proportion of both battle (58%) and nonbattle (71%) casualties and the Marine Corps had the highest battle casualty rate (0.52 per 1000 personnel) and nonbattle casualty rate (0.31).