Background: Despite medical advances, up to 70% of health outcomes are due to social determinants of health (SDoH) - the conditions in which people live and work that shape whether basic needs (e.g., housing, food) are met. These associations are especially well documented for cardiovascular disease (CVD). In response, health policy leaders recommend screening and referral (S&R) for unmet needs in clinical settings, and the American Heart Association recently concluded that the most significant opportunities for reducing CVD death and disability lie with addressing the social determinants of cardiovascular outcomes. A limited but promising evidence base supports these recommendations but more rigorous research is needed to guide how best to intervene on unmet needs that affect health. Significance/Impact: This project addresses the Office of Social Work’s priority to link Veterans with resources and services in support of treatment goals, the Office of Patient Centered Care and Cultural Transformation’s priority to enhance the physical, emotional, and social well-being of the whole person, the Office of Health Equity’s priority to reduce disparities, and the HSR&D priorities of health equity and population health. Our study will provide much-needed evidence to document the burden of Veterans’ unmet needs, inform how best to address unmet needs, and assess how such a process can affect adherence (to medications and appointments), utilization, and clinical outcomes. Innovation: VA currently systematically screens for only two unmet needs (homelessness and food insecurity). Identification of other unmet needs (and referral to address them) occurs on an ad hoc basis, with varying approaches among clinics/ clinicians. We will implement comprehensive screening of eight unmet needs and systematic referral, developing tools and processes that, if efficacious, can be implemented within VA (and other) clinical systems. VA is currently funding several studies related to SDoH, but none test interventions that systematically identify a wide range of unmet social needs among Veterans and connect Veterans with identified needs to social service resources. Specific Aims: 1) Describe the burden and distribution of eight unmet needs (i.e., housing; food insecurity; utility insecurity; transportation; legal guidance; employment; safety; and social isolation) among Veterans with or at-risk for CVD, and identify their associations with sociodemographic characteristics, and baseline health- related behaviors and clinical outcomes; 2) Compare the effects of three S&R study intervention conditions of varying intensity on Veterans’ connection to new SDoH resources (primary outcome), reduction of unmet needs, adherence, and clinical outcomes, and 3) Identify barriers and facilitators to Veterans’ connecting with social services and having needs met, and explanatory factors for observed RCT outcomes. Methodology: We propose a 3-year, two-phased mixed methods study. In Phas...