ObjectiveTo examine the impact of the Affordable Care Act (ACA) health insurance exchanges (Marketplace) on the rate of uninsured discharges in Texas.Data Source and Study SettingSecondary discharge data from 2011 to 2019 from Texas.Study DesignWe conducted a retrospective study estimating the effects of the ACA Marketplace using difference‐in‐difference regressions, with the main outcome being the uninsured discharge rate. We stratified our sample by patient's race, age, gender, urbanicity, major diagnostic categories (MDC), and emergent type of admissions.Data Collection/Extraction MethodsWe used Texas hospital discharge records for non‐elderly adults collected by the state of Texas and included acute care hospitals who reported data from 2011 to 2019.Principal FindingsThe expansion of insurance through ACA Marketplaces led to reductions in the uninsured discharge rate by 9.9% (95% CI, −17.5%, −2.3%) relative to the baseline mean. The effects of the ACA were felt strongest in counties with any share of Hispanic, in counties with a larger population of Black, and other racial groups, in counties with a significant share of female and older age individuals, in counties considered to be urban, in high‐volume diagnoses, and emergent type of admissions.ConclusionsThese findings indicate that the ACA facilitated a shift in hospital payor mix from uninsured to insured.