Summary: The National Defense Stockpile is composed of strategic and critical materials that can be used in times of national emergency. The stockpile was established to minimize dependence on foreign sources of these materials. Because of changes in mobilization planning and modernization of weapon systems, stockpiling requirements for many materials have been reduced dramatically during the last two decades. The Defense Logistic Agency's Defense National Stockpile Center manages the stockpile program and is responsible for the sale of materials that exceed stockpile requirements. Concerns have arisen over whether existing cash balances and projected collections from stockpile gross sales will meet all expected stockpile transaction fund outlays for fiscal years 2000-2010. GAO found that the National Defense Stockpile transaction fund's projected long-term outlays exceed projected collections from gross sales. The projections do not include all likely outlays, so the timing and size of a gap between available funds and outlays is unclear.