Forensic mental health evaluation systems have undergone major changes during the past two decades, and the variability of service delivery systems across states is significant. We compared assessments of competence to stand trial and criminal responsibility in three states with different systems for forensic mental health evaluations: Michigan, Ohio, and Virginia. Although all three states use comparable legal criteria to judge competence and criminal responsibility, we found large, statistically significant differences among the states in the proportion of defendants referred for evaluation who were assessed as incompetent or not criminally responsible. In addition, significant differences were found in the diagnostic and offense categories of defendants referred for evaluation. Our findings suggest that the structure of a system for providing forensic evaluation services may significantly affect both the group of individuals referred for evaluation as well as evaluation outcome.