Depleted uranium, a component of some weapons systems, has been in use by the U.S. military since the 1991 Gulf War. Military personnel have been exposed to depleted uranium as the result of friendly fire incidents, cleanup and salvage operations, and proximity to burning depleted uranium-containing tanks and ammunition. Under a Congressional mandate, the Department of Defense sought guidance from the Institute of Medicine in evaluating the feasibility and design of an epidemiologic study that would assess health outcomes of exposure to depleted uranium. The study committee examined several options to study health outcomes of depleted uranium exposure in military and veteran populations and concluded that it would be difficult to design a study to comprehensively assess depleted uranium-related health outcomes with currently available data. The committee further concluded that the option most likely to obtain useful information about depleted uranium-related health outcomes would be a prospective cohort study if future military operations involve exposure to depleted uranium. The book contains recommendations aimed at improving future epidemiologic studies and identifying current active-duty military personnel and veterans with potential DU exposure.