Women account for about half of all HIV infections globally. Sexual transmission is the dominant mode of HIV transmission to women and there is a concomitant, associated epidemic of transmission to infants. The majority of HIV infections in women are in sub-Saharan Africa with a disproportionate burden in young women under 25 years old. HIV acquisition and prevention in women is complex and influenced by biological, behavioral and structural factors. Efforts to reduce HIV infection in women in sub-Saharan African could play a substantial role in altering global HIV trajectories. Increasing access to sexual and reproductive health services, addressing gender based violence and social instability , reducing poverty and sex for survival, and encouraging greater male responsibility are critical short-to medium term interventions. Efforts to find a microbicide and HIV vaccine need to be matched with efforts to deepen understanding of HIV acquisition in the female genital tract to inform development of targeted molecules for HIV prevention.