Mental health courts (MHCs) are criminal courts with dockets exclusive to persons with mental illness. They were created to help stem the tide of persons with mental illness revolving in and out of the criminal justice system. A precondition of all MHCs is that participation is voluntary. However, it is unclear whether the courts ensure that participation decisions are indeed voluntary or view them as a mere formality. The proposed study has three main objectives. The first is to determine the level of awareness of voluntary participation in MHCs among persons enrolled in the courts and the factors that influence level of awareness. The second is to determine the level of understanding of MHC requirements among persons enrolled in the court and the demographic, mental health, and criminal justice characteristics that associate with understanding. The third is to determine whether level of MHC comprehension at entry predicts future success/failure in the court. Our study was designed with three stages. In Phase I, 200 defendants from two cooperating MHCs (one in the Northwest and one in the Northeast) will be interviewed. Interviews will consist of demographic, criminal and mental health history questions as well as the administration of several standardized measures assessing symptomatology, adjudicative competence, insight, and perceived coercion. MHC awareness, understanding, and appreciation will be assessed. In Phase II, outcome data will be collected for a one-year period following the Phase I interview. Outcome data, which will come from objective record reviews, will include success/failure measures such as number of re-arrests, days hospitalized, status review hearings mandated and attended, jail days, and graduation rates. Findings from our study have the potential to help MHCs realize their goals. For example, if MHC comprehension is predictive of success, as theorized, training programs to increase understanding could be developed and incorporated into MHC practices.