In 1991, about 150 general practitioners in 37 health care units in the county of Oslo introduced computerized systems of case records which replaced the previous paper records. The hardware units were located outside the units, and were physically interconnected by a large computer network within the county of Oslo. By losing physical contact, the general practitioners also lost control of their patient records. The files could be looked into and manipulated with or without the doctors' knowledge. It was no longer clear who was responsible for the computerized case records. These experiences are discussed, paying attention to the Norwegian legislation and official regulations in the area. The conclusions are that a health care unit using EDP should have its hardware at the unit itself. The chief doctor of the unit should be responsible for the daily management of the EDP-unit, and for safeguarding the confidentiality of the patient records.