Recently, we have experienced with various changes in the health insurance. Korean government is implementing the prospective payment system(PPS) as a pilot project to reduce medical expenditure. Case management is an effective way to reduce costs, while not sacrificing quality of service, under the PPS. In this study, the integrated decision support system(DSS) for case management was presented to support two case management activities ; utilization management and discharge planning. This system can be used in three ways ; prospective, concurrent, and retrospective management. By monitoring cases from medical record database, the DSS provides basic patient information, payment information, medical service information to the case manager. In the future, data warehouse should be introduced to integrate various databases related to case management and to improve quality of information produced by the DSS.