Summary: The Defense Department (DOD) projects that its costs for peacekeeping operations in Bosnia will reach $6.4 billion through June of this year, including $1.6 billion for fiscal year 1998. This estimate assumes that U.S. forces will withdraw by June 1998. Additional funding will be required if the U.S. presence in Bosnia is extended beyond that date. Revised budget-quality estimates for fiscal years 1998-99 are unlikely until key decisions are made. To be as accurate as possible, estimates should be based on NATO and U.S. decisions about the mission in Bosnia, the military tasks, force size, and logistical and other factors. Also, the military is considering additional ways to reduce costs. To meet Congress' legislative calendar, DOD plans to amend its fiscal year 1999 budget in March 1998 and request supplemental appropriations for fiscal year 1998. However, if NATO and the United States have not decided on the force size and other details by March, then budget-quality estimates may not be possible at that time.