The members of the Bundesverband Medizinischer Auftragsinstitute (BVMA) or Federal Association of Contract Research Organizations (CROs) are scientific enterprises offering services in clinical trials of drugs. In order to guarantee high quality services, all members of the BVMA underwent an independent external system audit according to a single predefined standard. The selection of one of several proposed audit organizations was based on personal presentation and two sample audits. The audit organization finally commissioned planned the system audit in co‐operation with the BVMA and prepared a special audit standard operating procedure (SOP). The facilities, equipment, and personnel qualifications as well as compliance of procedures with GCP standards and the companies' SOPs were inspected in 17 member CROs. The overall result of the system audit was positive with no serious findings indicating impairment of the quality of services offered. The remaining findings were classified in 31 cases as ‘major’ (significant deviation from GCP and SOPs without impairing quality of services) and in 163 as ‘minor’ (insignificant deviation). The audit findings were described for each CRO in an audit report that required a response from the audited CRO within 28 days. If major findings were not remedied within 9 months, a follow‐up audit was to be conducted. The feedback of the audited members was mainly positive. This system audit has documented the high quality of the BVMA members. Regular audits are planned in the future and will be prepared by a newly‐established BVMA ‘quality assurance’ working group.