HIV infection impacts the lives of young girls and women globally, with both populations being socially and biologically susceptible to HIV acquisition. The predominant mode of transmission in most parts of the world is heterosexual contact; however, injection drug use is an important transmission mode in Central and Eastern Europe as well as in North America. In HIV-infected women, cervical disorders (including those related to human papillomavirus infection and cervical intraepithelial neoplasia), Candida vaginitis, and pelvic inflammatory disease may be more frequent and severe. Fertility is negatively affected by HIV infection, and HIV infection increases adverse pregnancy outcomes in resource-poor settings. In addition, women are more likely to have antiretroviral treatment side effects, and certain antiretroviral regimens may impair contraceptive efficacy. Prevention strategies are presently not female-controlled.