MTN-009 is a multi-site, cross-sectional study that will provide an estimate of the prevalence of ARV resistance in the population of women who present to study sites to be pre-screened or screened for participation in an HIV prevention trial. To date, a comprehensive surveillance of HIV drug resistance in newly diagnosed women of reproductive age has yet to be undertaken. The primary goal of MTN-009 is to assess the frequency of HIV drug resistance mutations among women who test HIV-positive when presenting to screen for participation in HIV prevention trials.