Abstract: Objectives: Increasing numbers of older adults are reentering community following incarceration (i.e., reentry), yet risk of incident neurodegenerative disorders associated with reentry is unknown. Our objective was to determine association between reentry status (reentry vs never-incarcerated) and mild cognitive impairment (MCI) and/or dementia. Methods: This nationwide, longitudinal cohort study used linked Centers for Medicare & Medicaid Services and Veterans Health Administration data. Participants were aged 65 years or older who experienced reentry between October 1, 2012, and December 31, 2018, with no preincarceration MCI/dementia, compared with age-matched/sex-matched never-incarcerated veterans. MCI/dementia was defined by diagnostic codes. Fine-Gray proportional hazards models were used to examine association. Results: This study included 35,520 veterans, mean age of 70 years, and approximately 1% women. The reentry group (N = 5,920) had higher incidence of MCI/dementia compared with the never-incarcerated group (N = 29,600; 10.2% vs 7.2%; fully adjusted hazard ratio [aHR] 1.12; 95% CI 1.00-1.25). On further investigation, reentry was associated with increased risk of dementia with or without prior MCI diagnosis (aHR 1.21; 95% CI 1.06-1.39) but not MCI only. Discussion: Transition from incarceration to community increased risk of neurocognitive diagnosis. Findings indicate health/social services to identify and address significant cognitive deficits on late-life reentry. Limitations include generalizability to nonveterans.