PROJECT SUMMARY/ABSTRACT As people with HIV (PWH) enter older adulthood, there is a growing public health need to preserve everyday functioning in aging PWH. PWH disproportionately experience adverse factors including neurocognitive impairment (NCI) and psychiatric (e.g., depression) and medical (e.g., diabetes) comorbidities relative to age- comparable peers without HIV. Together, these factors put older PWH at risk for everyday functioning decline. Despite this, there are few studies on the longer-term patterns and correlates of everyday functioning change in PWH, and there is no well-validated multivariable risk index informed by such longitudinal data. Therefore, the research aims of this F31 will delineate unique longitudinal trajectories of everyday functioning in PWH; and develop and initially validate a risk index of adverse and protective factors based on longitudinal modeling to identify PWH at risk for functional decline. This project will be conducted with support from an interdisciplinary mentorship team at the University of California, San Diego (UCSD) HIV Neurobehavioral Research Program (HNRP), a leading research center with experts in HIV and aging. The proposed F31 will leverage access to two archival longitudinal studies: CNS HIV Antiretroviral Therapy Effects Research (CHARTER; N = 704) and Multi-Dimensional Successful Aging Among HIV-Infected Adults (N = 106), that were conducted and/or coordinated at the HNRP. Accordingly, the specific aims are to: 1) identify unique everyday functioning trajectories in a development dataset (CHARTER); 2a) develop a prediction model using adverse predictors for functional decline in the development dataset; 2b) validate the model in the development (CHARTER) and validation (Successful Aging) datasets; and 3) determine if positive psychological factors add incremental value to predicting functional decline. The training plan proposes rigorous statistical training in developing advanced longitudinal predictive models of everyday functioning, combined with specific mentoring in the understanding and uses of biopsychosocial variables relevant to aging PWH as potential predictors. This F31 application is in line with the National Institute of Aging’s (NIA) mission to support and conduct biological, clinical, behavioral, and social research on aging; in addition to their mission to foster the development of research and clinician scientists in aging. It is also in line with an NIH Office of AIDS Research (OAR) priority for well-validated, multivariable indices that combine a range of biological to behavioral measures to predict which PWH are at high-risk for adverse outcomes. The opportunities afforded via this F31 mechanism will facilitate the applicant’s professional development toward becoming an independent academic neuropsychologist dedicated to promoting successful aging among older PWH.