Hokkaido university picture archiving and communication system (HU-PACS) began clinical service in the Hokkaido university hospital in 1989. For the first 5 years the service was limited to the radiology department and the outpatient clinics. This paper describes the outline of the HU-PACS, how we have extended the service to all wards and managed the increasing image data accompanied by the installation of new CTs and MRI since 1994. A plan of future HU-PACS is also described.