Among U.S. offenders, both ethnic minorities and persons with mental illness are overrepresented. In communities, ethnic minorities are less likely than European Americans to receive mental health treatment, despite having similar need. Many barriers to treatment (e.g., financial and transportation) are removed in prisons; therefore, we sought to understand whether and how ethnicity relates to identification of mental illness (a proxy for treatment receipt) among prisoners. Due to the growth of the Latino population, we focused on Latino offenders. We examined records from two states with high proportions of Latino offenders to determine whether the likelihood of being identified with a mental illness differed by ethnicity. Offenders who had a mental disorder were disproportionately likely to be European American or African American and less likely to be Latino. We offer suggestions for future research on ethnic disparities in correctional mental health to promote best practices with vulnerable offenders.