PROJECT SUMMARY/ABSTRACT There is increasing evidence that gay, bisexual and other men who have sex with men (GBMSM) experience dual epidemics of HIV and intimate partner violence (IPV), yet understanding of the synergies between these two epidemics is underdeveloped. Estimated prevalence for receipt of IPV among GBMSM range from 12% to 78%. Emergent evidences demonstrates associations between the experience of IPV among GBMSM and participation in risk behaviors that heighten the risk of HIV (i.e. substance use). Beyond the indirect behavioral associations between IPV and HIV, less is known about direct pathways through which IPV may increase HIV acquisition risk among GBGBMSM. According to Schafer’s theoretical model, IPV not only contributes to behavioral risk, but also to immunologic change that impacts HIV risk – but all of this evidence comes from studies of heterosexual women. With the identification of HIV-specific immunologic dysfunction associated with IPV, we are able to further investigate upstream factors, including minority stressors that may contribute to such changes, as well as protective measures such as coping and resiliency processes. We hypothesize that experiences of IPV (including victimization, perpetration, and bi-directional IPV), in the context of minority stress, increases both indirect behavioral (sexual behavior, substance use), and direct biological (STI) and immunologic risks for HIV infection among GBMSM. To fill the critical gap in knowledge, we propose an innovative 24-month cohort study of partnered HIV-negative GBMSM in SE Michigan, to identify the pathways and points of intervention between IPV and HIV risk for GBMSM. Prior research is limited by cross-sectional designs, inconsistent measures of violence, and inattention to important psychosocial and structural factors that co-occur with both IPV and HIV, and may moderate or mediate relationships. We address these limitations by employing a rigorous cohort design, measures of IPV that are specific for GBMSM, considering the role of IPV victimization, perpetration and bi-directional IPV, and consider the multiple minority stressors and stress response behaviors that may shape both IPV and HIV risk behaviors, and measure indicators of HIV-specific immunologic dysfunction, biological risk (STI) and behavioral risk. The proposed research activities include a prospective 24- month cohort of 360 HIV-negative partnered GBMSM (>18 years) recruited in SE Michigan. The overall aim of the proposed activities is to provide new knowledge of how victimization or perpetration of IPV shapes engagement in HIV prevention and risk behaviors.