Southern Africa continues to bear a disproportionate share of the global burden of HIV: 35% of HIV infections and 38% of AIDS-related deaths in 2007 occurred in this sub-region. Southern Africa also experiences high levels of population movement, voluntary or forced, and comprises a diversity of people, including contract labor migrants, irregular migrants, families of migrants, refugees, trafficked persons and mobile workers such as truck drivers and mine workers. Furthermore, migrants have loved ones back home, who may face their own vulnerabilities, as the family breadwinner is away. This regional assessment, commissioned by the United States Agency for International Development (USAID) and funded by the PEPFAR Southern Africa Prevention Initiative, examines the migration patterns and the HIV vulnerabilities faced by migrants and mobile workers in the southern Africa region. It also investigates the main challenges faced by these groups in accessing HIV-prevention services. Finally, the report identifies opportunities for programming and prioritizes key activities that should be pursued in the region so as to lessen the overall HIV vulnerabilities of migrants, mobile workers and the communities within which they interact.