The Hospital District of Varsinais-Suomi consists of five hospitals for non-psychiatric diseases to deliver specialised health care for the population of 440000 inhabitants in South-western Finland. We have applied an open regional information system to aid clinical resource management in such a complex expert organisation. The main areas of application have been assessment of inpatient care usage in different communities and in different diagnosis-related-groups (DRG), measurement of length of hospital stay in different DRGs and comparison of DRG unit weight costs of different hospitals. The open structure of the data base and its distribution to all parties of health care professionals has resulted in mutual decisions on structural changes and increased cost containment activities.