Many states have expanded Medicaid eligibility to reach a wider array of vulnerable and historically uninsured populations. While Medicaid cannot pay for medical services provided in prisons or jails, people who are arrested and incarcerated can enroll in Medicaid and become eligible for benefits in the community. Given the high prevalence of mental health issues, substance abuse, and chronic health conditions among criminal justice populations, providing health care services to them could improve public health and public safety outcomes. This brief highlights initiatives in Arizona and Washington State through which Medicaid and correctional agencies exchange information to support enrollment in Medicaid.