This study assesses the likelihood of rearrest among a cohort of all adults (N = 1,438) released from the Massachusetts state prison system who received mental health services while they were incarcerated. All individuals were followed for 24 months. The analysis focused on four classes of variables: demographic characteristics, clinical history, criminal justice history, and postrelease supervision. These analyses showed that criminal history factors—a juvenile record and a history of multiple previous incarcerations—were significant risk factors, but that clinical factors, including a history of substance abuse, were not. Overall, the models developed here look much like the ones that would be observed in the general offender population. The implications of these findings for criminal justice and mental health policy are discussed.