Case management has become a core component in the delivery of long term care services. It is widely viewed as a mechanism for linking and coordinating segments of a service delivery system (within a single agency or involving several providers) to ensure the most comprehensive program for meeting an individual client's needs for care. Although there is some consensus regarding generic case management functions, the role of case manager is implemented with considerable variation and has different meanings in various settings. This paper presents a model for analyzing case management that is contingent on the delivery system. Four distinct long term care delivery system types are examined: Channeling, Basic and Complex, the Social/Health Maintenance Organization, and the Veterans Administration. Each is described with specific emphasis on the underlying financial arrangements, target populations, and gatekeeping mechanisms. The main argument of this paper is that the case management function that is implemented in each of these delivery systems will be differentially effective and efficient given the assumptions, goals, parameters, and constraints operating in the four systems. (BL)