PROJECT SUMMARY/ABSTRACT The US South has a greater proportion of HIV transmission associated with drug use than any other US region, and African Americans are disproportionately affected. Drug use stigma is a significant barrier to engagement and retention at every stage of the HIV prevention and care continuum. HIV-related stigma- reduction interventions in healthcare settings have shown positive outcomes, feasibility, and acceptability in the US and globally. However, few of these interventions address drug use stigma. Consequently, there is a critical need to understand how drug use stigma impacts engagement and retention in HIV services for African Americans who use drugs and to develop targeted interventions and programs to reduce drug use stigma. Failing to elucidate and actively address drug use stigma will result in stigma remaining a barrier to HIV services for a key population and in the region most affected by HIV in the US. The long-term goal is to develop an evidence-based drug use stigma-reduction intervention that can be implemented in HIV services, and ultimately reduce racial disparities in the HIV prevention and care continuum. The overarching objective for the proposed project is to use mixed methods to elucidate how drug-related stigma impacts engagement and retention in HIV services and use these findings to select, adapt, and pretest an evidence-informed HIV stigma-reduction intervention to address drug use stigma and other intersecting forms of stigma. The Specific Aims are: Aim 1. To conduct mixed methods research to assess and examine drug use stigma in human service settings among people who use drugs and health clinic staff. Aim 2. To select and adapt an evidence-informed HIV stigma curriculum to reduce drug use stigma and discrimination and to increase/improve engagement and retention in the HIV prevention and care continuum among people who use drugs. Aim 3. To pretest the adapted stigma and discrimination reduction curriculum to evaluate preliminary acceptability and feasibility. This research is innovative because it will shift current research paradigms regarding drug use stigma via the use of human-centered and status-neutral approaches. The proposed formative research will lay the groundwork for subsequent research to test the efficacy and preliminary impact of the tailored drug use stigma-reduction intervention. This study aligns with the high-priority areas identified in the NIH HIV/AIDS Research Priorities, specifically research to ultimately reduce health disparities in HIV incidence.