Research suggests incarcerate populations have high rates of chronic medical conditions. Because of the association of having a mental illness (MI) with a variety of medical conditions, incarcerates in psychiatric treatment may have an even higher rate of co-occurring chronic medical conditions. In this study, multivariate logistic regression models compared the odds of having any of 15 chronic medical conditions for a sample of 289 adult male and 142 adult female jail detainees in psychiatric residential treatment, with National Comorbidity Survey Replication participants representing the non-institutionalized U.S. population. After controlling for model covariates, the detainee sample had higher lifetime odds for 4 of the 15 conditions: severe headaches, strokes, chronic lung disease, and epilepsy/seizures. Female detainees, participants with one or more MIs, and older participants had the highest odds of having any chronic medical condition. The implications for coordinating primary medical care with psychiatric treatment for detainees with MI are discussed. (Published Abstract)