This study reports the results of the most recent in a series of cross-sectional surveys undertaken by a research consortium led by the Human Sciences Research Council (HSRC). The consortium includes local researchers from the South African Medical Research Council, National Institute of Communicable Diseases, Global Clinical and Viral Laboratories, and University of Cape Town, as well as international members from the US Centers for Disease Control and Prevention, UNAIDS, and UNICEF. Presenting new methodologies, innovative approaches, and important advances in assessment, the study is essential reading for all stakeholders working on HIV in South Africa or globally.