The microbiota of the human vagina can affect the health of women, their fetuses, and newborns. Bacterial vaginosis (BV) is the most prevalent form of vaginal infection in women of reproductive age, affecting 8% to 23%, and is the most common etiology of vaginal symptoms prompting women to seek medical care. While traditional cultivation has identified numerous BV-associated bacteria involved in these processes, recent advances in molecular biology have facilitated the detection and identification of bacteria without cultivation, some of which have not previously been described or well characterized. A more complete understanding of vaginal microbial populations resulting from the adoption of molecular tools may lead to better strategies to maintain healthy vaginal microbial communities-thus enhancing women's health-and will create opportunities to explore the role of novel bacteria in reproductive tract diseases. On November 19-20, 2008, the NIH convened a workshop of experts in the field of research and clinical practice related to BV in order to discuss how these new advances should be interpreted and applied to research in progress and collaborations between relevant disciplines. This paper summarizes the presentations of this workshop and outlines general recommendations arising from the related discussions. Future studies of BV and its associated adverse outcomes should determine if specific combinations of organisms are more pathogenic than others, and causally associated with different adverse events. Moreover, determination of causality will depend not only on more precise categorization of the vaginal microbiota, but also on variations in the host environment that may be associated with changes in bacterial communities over time. In this report, we offer suggestions and recommendations that we hope will facilitate conduct of consistent approaches to collaborative efforts towards advancing our understanding of the vaginal microbiota and its impact on human health.