The standard specifies the formal requirements for the performance of clinical investigation of medical devices. It serves particularly for the protection of study populations employed in the investigation. It shall also contribute to scientifically tenable investigation results. This standard is essentially different from the currently applicable standard in the following points. It includes the hitherto independent part 2 of the standard, which specifies the content of the investigation plan. The standard is based closely, as far as it makes sense, on the regulations on clinical investigation of medicinal products, in order to relieve the application for institutions which investigate both medicinal products and medical devices. The responsibility of the sponsors, the doctors (monitors) assigned by the sponsors and the clinical investigator are summarised in separate clauses. This relieves the fulfilment of each task and thereby contributes to correct performance and cost reduction. This standard is directed at manufacturers of medical devices and doctors as well as institutions which perform clinical investigation of medical devices. The European Standard has been prepared by ISO/TC 194 "Biological evaluation of medical devices" (secretariat: DIN) in collaboration with CEN/TC 258 "Clinical investigations of medical devices" (secretariat: DIN) with the essential contribution of German experts. At DIN, the responsible Working Committee is NA 027-02-20 AA "Klinische Prüfungen" ("Clinical investigations") of NAFuO.