In the 30 years following world warll, major changes in concepts of mental health and provision of mental health service have been apparent. These trends are a product of social ideologies, changing public opinion, fiscial conditions, and new technologies. Deinstitutionalization of mental patients was a movement that aims to minimize the amount of care provided by out patient agencies in the community. Case management has been defined as a systematic process of assessment, planning, service coordination and/or referral, and monitoring through which the multiple service needs of clients are met. Nurses are the most qualified professionals to provide case management services to the chronically mentally ill who are living in the community. Case management optimizes the client`s self-care capability and provides for quality health care along a continuum, decreases the fragmentation of care, improves the client`s quality of life, and provides for cost containment by the prevention of unnecessary duplication of services or institutionalization. The nurse case manager is the bridge linking community services with those provided by the mental health clinics. Each nurse case manager will act as provider of services in her field of expertise, as well as coordinator of those services provided by others.