The concept of case management has become very popular since 1970 because it promotes the free choice of service and saves money for social agencies. This paper will discuss the basic concept of case management, the development background, the social work root, the professional roles, and the process of practice in case management. The first and second sections of the paper present the definition and concept of case management as the mutual trusting and empowering relationships between case manager and client. It is the coordination and integration of services delivery systems to ensure that the client receives the most appropriate services. The third and fourth sections of the paper present the development background of case management and its difference from social casework. The impact of "de-institutionalization" upon the rapid growth of case management was discussed in relation to the large number of patients discharged from many state hospitals during the period of 1960's to 1980's. The fifth and sixth sections of the paper discuss the relationships between case management and social work principles as well as professional roles of case management in human services and health care industries. The seventh and eighth sections of the paper discuss the basic functions and process of practice of case management explaining the major tasks of linking clients to service delivery systems, assessing client's capacity in using services, and motivating client's interest in using services. The practice of outreach, referral, prescreening, assessment, care planning, monitoring, reassessment and disengagement process was discussed. The paper concludes that case management is a very important method in linking client to service delivery systems. Case manager needs to equip himself or herself with a broad knowledge of social casework, group work, community organization, management skills, research methods, ability to integrate services and monitoring service programs.