Background : Recently, we have experienced various changes in the healthcare environment. Healthcare organizations are facing a financial crisis due to more competitive relationships among themselves as well with low health insurance fees. The purposes of the current study were: (1) to develop a data warehouse-based system for evaluating and monitoring the case management activities, and (2) to measure and analyze its effects. Methods : In order to collect the data for the study, the database on discharged patients was utilized at a university hospital located in Seoul from June 1, 2002 through December 31, 2002. Initially, a data warehouse was built for the case management system. The case management activities were analyzed using structured methodology to establish the case management system. Results : The findings of this study were as follows: (1) A case management system was developed to make it possible to monitor of healthcare quality and resource utilization. The Case management System included monitoring functions regarding utilization reviews, critical pathways, and clinical indicators. (2) Utilizing the case management system, unplanned readmissions were documented among total discharged patients during two months from November 1, 2002 through December 31, 2002. The unplanned readmission rate was 2.3%(276 patients) in total of 11,960 discharged patients. Among them 81 patients(0.7% of total discharges, 29.3% of unplanned readmission) were readmitted to the same physician in charge under the same diagnosis. No significant differences were found in the demographic variables such as gender and age among the patients. (3) After implementing the case management system, 2.9% of average length of stay reduced. Applying cost-benefit analysis, the 2.9% reduction of length of stay represents net profit of ${\backslash}$ 279,592,000 in the year of 2004. In addition, applying value acceleration analysis, cumulative net benefit of ${\backslash}$ 1,481,000,000 was expected by the year of 2007. Also we were able to expect ${\backslash}$ 247,800,000 of cumulative benefit for the prospective 5 years in value linkage analysis. It represents average ${\backslash}$ 787,700,000 of pure net benefit a year. Conclusion : The value of present study would be not only implementing the knowledge management system into the existing case management activities, but also evaluating its effects and estimating its financial benefits. This study suggested that the case management system would be a supportive tool for monitoring and improving the quality of healthcare, and a cost-effective tool for increment of healthcare organization's financial benefit.