International commitment to the human immunodeficiency virus-acquired immunodeficiency syndrome (HIV/AIDS) epidemic has grown rapidly in recent years, stimulated by the leadership of the Joint United Nations Programme on HIV/AIDS (UNAIDS) and its cosponsors and supported by a range of new mechanisms. These include the World Bank's Multi-Country AIDS Program, the Global Fund to Fight AIDS, Tuberculosis and Malaria, and most recently, the U.S. President's Emergency Plan for AIDS Relief. Global HIV/AIDS spending grew from an estimated US$300 million in 1996 to US$2.8 billion in 2002. The critical need to ensure that available resources are used effectively places unprecedented responsibility on monitoring and evaluation (M&E). Improving M&E, in turn, requires a sustained commitment to capacity building and systems development, particularly in countries confronted by limited public sector capacity and human resources, problems exacerbated by widespread poverty and AIDS mortality. In this article, the author summarizes the World Bank's recent experiences with M&E capacity-building approaches in support of the development of national M&E frameworks and operational M&E plans and budgets, primarily within the context of the World Bank's Multi-Country AIDS Program. Through its multicountry AIDS program, the World Bank has joined UNAIDS and other United Nations and bilateral agencies as major partners of national AIDS councils in Africa. These multisectoral, national coordinating bodies are typically the World Bank's point of entry and its primary focus for M&E capacity-building support. (Contains 2 tables.)