The purpose of the present study is to develop a CRM system for patients with diabetes mellitus. The subjects were outpatients who visited a university hospital from March, 1997 thru February, 2003. The distributions of outpatients, types of disease, revenues, exemption of designated doctor's fee, and no-show rate were obtained for each department by utilizing the OCS database. Quantitative and Qualitative data were collected from the diabetes patients chosen based on the distribution. The goals of applying the CRM are not to provide diabetes patients with general medical services, but to provide individually-tailored medical services by utilizing the information obtained from the departments of moment of truth(MOT) effectively and integrating the management of work process and human resources. For an effective application of the CRM, it needs to be performed to support the strategic objectives and incorporate management strategies that are appropriate for internal and external environments. That modeling for diabetes patients includes campaign activities, customer management process, and the functions of predicting and diagnosing the patients and managing the medical services of MOT departments and referral system.