Hospital Presumptive Eligibility (HPE) is a temporary Medicaid insurance at hospitalization that offsets costs of care, increases access to postdischarge resources, and provides patients with a path to sustain coverage through Medicaid. Because HPE only lasts up to 60 days, we aimed to determine Medicaid insurance status 6 months after injury among HPE-approved trauma patients and identify factors associated with successful sustainment.Using a customized longitudinal claims data set for HPE-approved patients from the California Department of Health Care Services, we analyzed adults with a primary trauma diagnosis (International Classification of Diseases version 10) who were HPE approved in 2016 and 2017. Our primary outcome was Medicaid sustainment at 6 months. Univariate and multivariate analyses were performed.A total of 9,749 trauma patients with HPE were analyzed; 6,795 (69.7%) sustained Medicaid at 6 months. Compared with patients who did not sustain, those who sustained had higher Injury Severity Score (ISS15: 73.5% vs. 68.7%, p0.001), more frequent surgical intervention (74.8% vs. 64.5%, p0.001), and were more likely to be discharged to postacute services (23.9% vs. 10.4%, p0.001). Medicaid sustainment was high among patients who identified as White (86.7%), Hispanic (86.7%), Black (84.3%), and Asian (83.7%). Medicaid sustainment was low among the 2,505 patients (25.7%) who declined to report race, ethnicity, or preferred language (14.8% sustainment). In adjusted analyses, major injuries (ISS16) (vs. ISS15: adjusted odds ratio [aOR], 1.51; p = 0.02) and surgery (aOR, 1.85; p0.001) were associated with increased likelihood of Medicaid sustainment. Declining to disclose race, ethnicity, or language (aOR, 0.05; p0.001) decreased the likelihood of Medicaid sustainment.Hospital Presumptive Eligibility programs are a promising pathway for securing long-term insurance coverage for trauma patients, particularly among the severely injured who likely require ongoing access to health care services. Patient and provider interviews would help to elucidate barriers for patients who do not sustain.Prognostic and Epidemiological; Level IV.