A survey of anaesthetic critical events based on voluntary anonymous reports was undertaken over a two and a half year period within a teaching hospital Department of Anaesthesia. At the end of the survey 167 reports were analysed. Human error was a contributing factor in 82% of events. Inadequate preoperative patient assessment or preparation, problems in the area of human/equipment interface and various stress factors for the anaesthetist featured significantly in the survey. The method enables the collection of objective data on factors contributing to anaesthetic and surgical risk and the formulation and evaluation of potential corrective strategies. It also facilitates harmonious peer review via individual and group feedback activities. The adoption of such a survey on a wider scale is seen as a valuable part of quality assurance in the continuing attempt to increase patient safety.