Hospitals are experiencing an increasing amount of financial difficulty due to government control of hospital rates since national health insurance has been implemented. The decision support system (DSS) was developed to provide cost and revenue information for the services rendered by each department in an effort to reduce costs. This information may be used to identify the causes of financial loss if cost exceeds revenue and to conduct variance analysis or portfolio analysis to improve financial situation of hospitals. The DSS was developed using a micro-mainframe interface approach where the mainframe computer collects and summarizes daily cost and revenue data and the micro computer computes the cost for each department. The significances of this paper are to determine the cost allocation basis and methods which are suitable to Korean situation and to apply DSS technology to the cost analysis.