INTRODUCTION: The aging process of the incarcerated population is a growing concern, yet there are few data on older adults in this demographic group. Hence, this study sought to examine the health status of older adults who are incarcerated in Mexican prisons and its association with the duration of their imprisonment. METHODS: This is a secondary analysis of the 2021 Mexico National Prisons Survey. We analyzed 50-year-old and older prisoners and performed a descriptive analysis of the sample's age, sex, sociodemographic variables, and chronic conditions. Multivariate analysis stratified by age was performed to assess the effect of the time spent in prison on older prisoners' health. RESULTS: The mean age was 56.95 (±6.4 SD), and the mean duration of imprisonment was 8.93 years (±6.94 SD). Regarding health conditions, 17.80% had diabetes, 29.62% had hypertension, 10.33% had suicidal ideation, and 40.87% were visually impaired, 17.01% had hearing impairment, and 17.64% had mobility impairment. Multivariate analysis revealed that among categories of imprisonment duration, longer time imprisoned was associated with an increased risk of diabetes and hypertension for all groups but was not associated with mobility impairment or suicidal ideation except in the younger group. CONCLUSION: Longer periods of incarceration appear to be associated with a greater occurrence of diabetes and hypertension in older prisoners. Sensory impairments and suicidal ideation are mainly identified in younger prisoners, while mobility impairments do not appear to be influenced by the time spent in prison. Further research needs to be done in prisons, where the addition of physical performance tests and cognitive tests could help further study geriatric conditions in older prisoners.