Background: Between 2009–2020, VA implemented primary, secondary, and tertiary interventions to prevent and end homelessness among Veterans, resulting in a 50% reduction in Veteran homelessness. The need to prevent new episodes of homelessness remains; the National Call Center for Homeless Veterans (NCCHV) is available 24 hours a day, 7 days a week to connect Veterans with resources to address housing instability. During a 2-year period, 60% of the 110,000 Veterans who contacted NCCHV reported being at risk of homelessness. Significance: The proposed study provides the opportunity to assess how NCCHV links Veterans who are at risk of homelessness with needed services to mitigate their housing instability, which is an important social determinant of health. This study is supported specifically by the Homeless Program Office and the U.S. Interagency Council on Homelessness. Innovation & Impact: Unlike other major initiatives to prevent and end homelessness among Veterans, NCCHV has not yet been studied; the proposed study will use NCCHV data linked with other administrative data sources and qualitative methods to explore homelessness prevention among Veterans, which will have important implications for the field at large. Specific Aims: (1) Describe characteristics and needs of Veterans accessing NCCHV using existing administrative data collected through NCCHV and VA’s electronic health record. (2) Assess Veterans’ outcomes following contact with NCCHV. (3) Identify optimal practices for linking Veterans with services following a contact to NCCHV. Methodology: This concurrent mixed methods study will include retrospective quantitative analyses examining Veterans’ contacts with NCCHV, quantitative and qualitative methods assessing how Veterans who are engaged with VA care are connected with services and associated outcomes (e.g., long -term housing stability, health care use, mortality), and observations of NCCHV responders and qualitative interviews with key informants exploring how providers connect Veterans with care following an NCCHV contact and identifying effective strategies. Next Steps/Implementation: This study is intended to identify optimal practices to ensure Veterans are connected with needed resources; future research may develop and study specific interventions to improve access to care and the prevention of homelessness. From a practice perspective, this study will identify intervention points for homelessness prevention as well as effective practices to further implement .