This Report presents the Department of Defense assessment of the relative contributionstoward the common defense and mutual security made by our NATO allies, our Pacific allies, (Japan and the Republic of Korea), and the countries of the Gulf Cooperation Council (GCC).Under legislative provisions dating to the Defense Authorization Act of 1981 (P.L. 96-342, Section 1006), the Department of Defense is required to compare the defense burdens borne by our allies,explain disparities, and describe efforts to eliminate such disparities. This Report addresses requirements originally set forth in the 1984 National Defense Authorization Act (P.L. 98-525), Title X, Section 1003, Defense Burdensharing, paragraphs a-d. The most recent baselinelegislation addressing this reporting requirement is the FY 1997 National Defense Authorization Act, Title X, Section 1084. This Report also covers burdensharing reporting requirements set forth in the FY 2000 Department of Defense Military Construction Appropriations Act (P.L. 106-52), Section 119. For the last four years, beginning with the FY 1997 Defense Authorization Act (P.L. 104- 201), Congress has recognized that there are multiple and diverse ways in which allies may share the responsibility for achieving mutual security objectives. The Department looks forward to continuing to work with the Congress in structuring a comprehensive and balanced framework within which to evaluate allied contributions to common defense and mutual security.