The selection of an electronic data processing system for use in the medical field is in many cases complicated by the fact that the tasks have not yet been defined accurately in detail. Therefore, the technical system planning may only be carried out on the basis of an organization study which, among other things, is to provide bases for answering questions about the structure of this system, about the places where subsystems should operate in the hospital, and about the individual levels of implementation. When selecting the system, the criteria to be taken into consideration include the technical efficiency, organizational range of application, reliability, assistance by the manufacturer and, last but not least, the cost - bearing in mind that, in the medical field, the weights may be placed quite differently from the commercial field. With this planning consideration should also be given to the possibilities of utilization not basing on a system of one's own.