Background: Veterans are more likely to report psychological distress, which also elevates their risk for certain social determinants of health, such as unmet social needs (e.g., housing instability). As the entry point for most Veterans into care, the presence of multidisciplinary members on integrated Patient Aligned Care Teams (PACTs) in primary care, such as social workers and Primary Care Mental Health Integration (PCMHI) providers helps to address the wholistic needs of these Veterans by providing increased access to additional resources that have found to improve patient outcomes. Significance: However, prior research has showed that these integrated PACTs continue to demonstrate significant variation in meeting the needs of Veterans with psychological distress and unmet social needs (even with the skillsets brought to the PACT by the new members) leaving opportunities to improve access. Due to the negative impact of the comorbid experience of psychological distress and unmet social needs on Veteran’s health on health, identifying ways to optimize access to care within these integrated PACTs is an opportunity to reach a broad array of Veterans. Innovation and Impact: The proposed research is innovative through its attention to an underdeveloped area of the healthcare structure, integrated PACT characteristics, and its relationship with access. Informed by prior PACT implementation literature and a conceptual framework on patient navigation, integrated PACT characteristics include: structural, provider-specific, and team behaviors. Our aims seek to use mixed methods to provide a comprehensive understanding from multiple perspectives on PACT characteristics predictive of improved access and identify associated processes to achieve access within integrated PACTs within this high need population. These results will provide immediate guidance to VHA on the types of evidence-based interventions that can be utilized and practice changes that may support those interventions in achieving access to care for Veterans with unmet social needs and psychological distress. Specific Aims: Aim 1 will identify integrated PACT characteristics (provider, structural, and team behaviors) that significantly predict initial engagement to care among Veterans with unmet social needs and psychological distress. Hypothesis: Integrated PACT structural, such as staffing, and team behaviors, such as team meetings will be the strongest predictors of initial Veteran engagement in care. Aim 2 will identify best practices and perspectives from members and administrators within high performing integrated PACTs on ways to achieve optimization of significant integrated PACT characteristics supporting high levels of engagement among these Veterans. Aim 3 will test a model of hypothesized relationships between integrated PACT characteris tics and access as measured by Veterans’ perceptions of care (perceived access), ratings of quality of care, and engagement in care. Methodology...