As the HIV epidemic has matured, a substantial proportion of new infections worldwide may be occurring within stable partnerships. Within the United States, blacks are disproportionately affected by HIV disease, and the drivers of this epidemic involve behavioral and structural factors. The 17th Conference on Retroviruses and Opportunistic Infections highlighted new insights into drivers of HIV infection in both of these populations. The conference also focused on new strategies to track the epidemic and to prevent HIV infection, including scale-up of HIV testing and of treatment of HIV-seropositive persons, and the use of oral and topical antiretroviral drugs to prevent HIV acquisition among HIV-uninfected persons.