Cost accounting according to diagnoses covering approximately 600 inpatients with 64 diseases in 20 departments of Kumamoto University was carried out. The reports of these results were automatically generated and used for individual departmental meetings with participating delegates. The administration of each department as well as the management of diseases was discussed at the meetings, and all departments were requested to provide a report of their discussions. We are planning to increase the number of patients in the sample group and to perform more comprehensive and accurate hospital cost accounting.