Objectives: To describe older jail inmates' predetainment use of acute care (Emergency Department (ED) or hospitalization in the 3 months prior to arrest) and their plans for using acute care after release.Methods: Cross-sectional study of 247 jail inmates age 55 or older assessing sociodemographic characteristics, health and geriatric conditions associated with predetainment and anticipated post-release acute care use.Results: 52% of older inmates reported predetainment acute care use and 47% planned to use the ER after release. In modified Poisson regression, homelessness was independently associated with predetainment use (RR 1.42, CI 1.10 -1.83) and having a primary care provider was inversely associated with planned use (RR 0.69, CI 0.53 -0.89).Conclusions: The Affordable Care Act extends Medicaid eligibility to all persons leaving jail in an effort to decrease post-release acute care use in this high-risk population. In addition, jail-to-community transitional care models that address the health, geriatric and social factors prevalent in older adults leaving jail, with specific focuses on linkages to housing and primary care, are needed to enhance the impact of ACA policies on acute care use for this population.2