The DoD has spent over $115 billion since the mid-1980s to develop a Ballistic Missile Defense System (BMDS) comprised of land, air, and sea-based elements -- such as missiles and radars -- working together as an integrated system. Since the cost to operate and support a weapon system accounts for most of a system¿s lifetime costs, the resources needed to fund BMDS could be significant as DoD fields an increasing number of BMDS elements. In 2005, DoD began planning to transition responsibility for supporting BMDS elements from the Missile Defense Agency to the services. This report assesses the extent to which DoD has: planned to support BMDS elements over the long-term; and identified long-term operation and support costs.