ABSTRACT The COVID-19 pandemic and racial justice movements have laid bare the structural problems in our healthcare system. Lack of health insurance directly impacts health care access and outcomes. Uninsured patients have catastrophic expenditures, higher rates of mortality, and more limited access to post-discharge resources that are critical for returning to work. These negative impacts are exacerbated among racial and ethnic minorities. We have an unprecedented and timely opportunity to study the uninsured in our nation. At the end of 2018, nearly 14% of the US population were uninsured, a number that has further increased with spikes in unemployment related to COVID-19. There is an urgent need to reduce insurance disparities. A potential solution, Hospital Presumptive Eligibility (HPE), enables hospitals to apply for emergency insurance for uninsured patients. HPE provides temporary Medicaid coverage (up to 60 days), but subsequently enables patients to enroll in Medicaid in order to continue coverage. In light of COVID-19, several states are broadening their HPE eligibility criteria. Little is currently known about factors influencing HPE acquisition, as well as Medicaid enrollment post-HPE and its association with access to care. In our preliminary work, minority patients, those with greater clinical severity, and patients requiring post-discharge services (including rehabilitation, long-term care) were all more likely to be approved for HPE. Among approximately 1000 HPE approved patients in 2018 at our institution, only 53% of those enrolled in Medicaid. We hypothesize that there are modifiable patient- and system-level barriers inhibiting Medicaid enrollment after HPE. As administrative and clinical registry data capture neither HPE approval nor Medicaid enrollment, we will analyze novel customized insurance datasets through the California Department of Health Care Services (DHCS) to evaluate HPE programs and identify improvement opportunities. The proposed work will be accomplished through 2 specific aims: (SA1) Among eligible HPE-approved patients, we will determine the sociodemographic, clinical and hospital factors associated with post-HPE Medicaid enrollment, and (SA2) to understand patients' experiences of process factors that contributed to or impeded enrollment in Medicaid following HPE approval. The time of hospitalization can be leveraged to acquire sustainable insurance coverage that improves patients' long-term health outcomes and reduces their risk of catastrophic health expenditures. Our study evaluates how HPE programs can best be targeted toward improving health outcomes and access to care, particularly among vulnerable minority patients.