Project Summary There remains an acute, critical need to study HIV/AIDS as approximately 32,000 individuals are infected annually in the U.S. and mortality globally remains at over 630,000 annually. The NIH Office of AIDS has four main priority areas for HIV/AIDS research: reduce the incidence, develop HIV cures, develop next generation therapies and address HIV comorbidities. The National Primate Research Centers are charged with supporting the national needs for nonhuman primate research, with a significant priority on supporting HIV/AIDS related research. The Southwest National Primate Research Center (SNRPC) actively supports research projects in each of the priority areas designated by the Office of AIDS research. There remains a current shortage of Indian origin rhesus macaques in the U.S. due to a ban on exportation and recent global pressures significantly exacerbating the supply. This has led to the increased demand for P51 supported animals to be used to supply HIV/AIDS projects. The SNPRC has been disproportionately affected by the national macaque shortage due to the small size of our SPF rhesus colony and the assumption of a greater responsibility for research using rhesus. The SNPRC resources serve not only a number of internal core scientists that are focused on infectious disease, but also a heavily external-facing research portfolio. The SNPRC supports > 230 active research requests from > 120 affiliated scientists, with >30 % of rhesus macaque projects completed onsite associated with HIV/AIDS related research. These requests have increased the demand for appropriate ABSL2 research holding space in order to support the upcoming HIV/AIDS related projects. This proposed P51 supplement will meet an urgent need to upgrade ABSL2 macaque holding space to support HIV/AIDS related research. Over the last decade several ABSL2 buildings and rooms have been removed from service and taken offline at SNPRC due to failing HVAC systems. This supplement will provide HVAC upgrades to eight ABSL2 rooms to bring them back into service to support rhesus macaque holding at SNPRC.