||In the recent past, the mental health system has responded to calls for deinstitutionalization and has had to deal with steadily decreasing flows of money. At the same time, a growing number of people who need treatment are finding themselves in the criminal justice system. The criminal justice system frequently finds it has to care for mentally ill individuals even though that is not their mission. In order to better address the needs of mentally ill individuals in both systems they have had to collaborate on behalf of those they serve. This study set out to explore the possibility of inherent problems in the way mental health and criminal justice professionals viewed each other, perceived barriers to collaboration, and possible inroads to better collaboration. Using a qualitative methodology based on the constructivist paradigm and systems theory, fourteen mental health and 15 criminal justice professionals were interviewed. Semistructured questionnaires in separate focus groups were used to explore their perceptions of each other, each otherâ€˜s systems, and barriers that individuals with mental illnesses in those systems face. The results indicated that mental health and criminal justice professionalsâ€˜ views varied according to their education, experiences with each other, and proximity of working with each other. The results also indicated that funding problems, low cross system education, service gaps, and inconsistency in professionalism inhibited collaboration between the two systems. Participants felt education regarding each systemâ€˜s philosophies, appropriately shared responsibilities, and understanding the limits both systems would help eliminate some barriers faced in collaboration. Participants said benefits of close collaboration would include higher success rates for mentally ill individuals, less recidivism in both systems, and increased professional satisfaction. Implications of the study indicated the need for increased education in both systems regarding the purpose, function, and philosophies of both systems. Also, leaders and front line professionals should focus on making their interactions with each other more consistent, clear, and available. Further research should investigate quantitative verification of the results, policy implementation to promote collaborative efforts, and educational efforts to improve the perceptions of mental health and criminal justice professionals of each other.