The number of older adults (age fifty-five or older) incarcerated in US prisons reached an all-time high just as COVID-19 entered correctional facilities in 2020. However, little is known about COVID-19’s impact on incarcerated older adults. We compared COVID-19 outcomes between older and younger adults in California state prisons from March 1, 2020, to October 9, 2021. Adjusted odds ratios (aORs) revealed an increasing risk for adverse COVID-19 outcomes among older age groups (ages 55–64, 65–74, and 75 or older) compared with younger adults, including for documented infection (aOR, 1.3, 1.4, and 1.4, respectively) and hospitalization with COVID-19 (aOR, 4.6, 8.7, and 15.1, respectively). Moreover, although accounting for 17.3 percent of the California state prison population, older adults represented 85.8 percent of this population’s COVID-19-related deaths. Yet a smaller percentage of older adults than younger adults were released from prison during the pandemic. The differential rates of morbidity and mortality experienced by incarcerated older adults should be considered in future pandemic response strategies regarding prisons.