Leading investigators in the area of HIV research from Johns Hopkins (JHU) and Makerere Universities (MU) propose to establish the Makerere University-Johns Hopkins University HIV Clinical Trials Unit-Kampala, Uganda to conduct critical HIV prevention and treatment research. This Clinical Trials Unit (CTU) consists of an administrative base at JHU and two Kampala clinical research sites (CRS). The MU-JHU Research Collaboration site will be affiliated with both the IMPAACT and the Microbicide Network applications, focusing on HIV prevention and treatment in women and children. The Infectious Diseases Institute site will be affiliated with the HPTN Network application with a focus on HIV prevention in adults. Both sites also have the capacity to expand to other network areas such as HIV vaccine end treatment studies. The clinical, data management, laboratory, and administrative resources and expertise necessary to screen, enroll, and retain HIV infected and uninfected participants in HIV prevention and treatment trials are currently available. The presence of the shared CAP-certified laboratory, community advisory boards, strong regulatory/QC sections, and local Ugandan IRB oversight coupled with extensive clinical trials experience will insure that all research is conducted to the highest scientific and ethical standards. The longstanding (>17 yr) relationship between JHU and MU investigators and support of the Uganda Ministry of Health has created a strong, productive, and mutually beneficial international center for HIV research that will be able to continue and expand through the funding of this application. Uganda has been at the forefront in HIV education, programs, and research in response to their devastating epidemic. However, rates of HIV infection in the 45,000 women in the Mulago hospital antenatal clinics yearly remain high (~11%), with transmission to neonates during pregnancy and breastfeeding. Women are economically and socially disadvantaged with limited capacity to protect themselves against infection. Access to HIV therapy is expanding, but lack of medical infrastructure and human capacity presents an ongoing challenge. Preventing HIV infection in adults and children and providing access to care to those infected is a worldwide public health crisis. The goal of this research unit is to find practical and affordable ways to accomplish this in a setting with limited resources.