Between 1990 and 2005, HIV prevalence rates in South Africa jumped from less than 1% to around 29%. Important scholarship has demonstrated how racialized structures entrenched by colonialism and apartheid set the scene for the rapid unfolding of the AIDS pandemic, like other causes of ill-health before it. Of particular relevance is the legacy of circular male-migration, an institution that for much of the 20th century helped to propel the transmission of sexually transmitted infections among black South Africans denied permanent urban residence. But while the deep-rooted antecedents of AIDS have been noted, less attention has been given to more recent changes in the political economy of sex, including those resulting from the post-apartheid government's adoption of broadly neo-liberal policies. As an unintentional consequence, male migration and apartheid can be seen as almost inevitably resulting in AIDS, a view that can disconnect the pandemic from contemporary social and economic debates. Combining ethnographic, historical, and demographic approaches, and focusing on sexuality in the late apartheid and early post-apartheid periods, this article outlines three interlinked dynamics critical to understanding the scale of the AIDS pandemic: (1) rising unemployment and social inequalities that leave some groups, especially poor women, extremely vulnerable; (2) greatly reduced marital rates and the subsequent increase of one person households; and (3) rising levels of women's migration, especially through circular movements between rural areas and informal settlements/urban areas. As a window into these changes, the article gives primary attention to the country's burgeoning informal settlements--spaces in which HIV rates are reported to be twice the national average--and to connections between poverty and money/sex exchanges.