PROJECT SUMMARY/ABSTRACT Alcohol use, common among PLWH, plays an increasingly important role in the risk for and management of HIV-associated comorbidities. Unhealthy drinking can exacerbate two highly prevalent HIV-related comorbidities/co-occurring conditions, chronic pain and physical inactivity, which in turn, can intensify alcohol use and affect physical and mental function in PLWH. We propose the Boston Alcohol Research Collaboration on HIV/AIDS – Comorbidity Center (Boston ARCH CC) as an extension of our Boston Alcohol Research Collaboration on HIV/AIDS (ARCH) cohort launched in 2011 and renewed in 2016 with funding from NIAAA. In Boston ARCH CC we target in randomized trials these two modifiable conditions, pain and physical inactivity, that have a critical impact on a variety of other HIV-related comorbidities. We will also support secondary analyses of the existing Boston ARCH cohort, and provide support and mentoring to trainees and investigators accessing the cohort. The Administrative Core will be responsible for the day-to-day management of the Boston ARCH CC and the operation of its components. In addition to the Administrative Core, Boston ARCH CC elements include two Research Project Components (clinical trials), and a Biostatistics and Data Management Core that leads our secondary analysis and training missions. The specific aims of the Administrative Core are to: 1) Provide a rich research environment for Boston ARCH CC investigators and trainees, and assure efficient progress of high-quality alcohol and HIV comorbidity/co- occurring condition science; 2) Centralize support for Research Project Component clinical trial implementation (e.g. Data Safety Monitoring, digital clinical trial recruitment and enrollment, ecological momentary assessments, alcohol biomarker tests), beyond what would be achievable by individual stand-alone projects; 3) Facilitate secondary data analysis, data sharing, and publication from analyses of Boston ARCH cohort data related to pain, physical inactivity, and physical and mental health function; 4) Offer resources and mentoring for early career investigators interested in engaging in alcohol and HIV research; 5) Engage in collaborative science within and beyond the Boston ARCH CC. The Administrative Core, with its scientific and administrative leadership and coordinated activities, will be essential for assuring that Boston ARCH CC achieves its goals to reduce alcohol and HIV-associated comorbidities.