Human error occurs in all walks of life, including medicine. Numerous studies demonstrate that iatrogenic complications account for many deaths, long-term disabilities and unnecessary expense. The study of these adverse events can be formalized in various ways in order to minimise the frequency and severity of complications. Incident monitoring borrows its methodology from the well proven airline, scuba diving and similar fields where "near miss" events are treated as seriously as actual events, because the near miss is often a pointer to a systematic problem which should be corrected. The areas of human performance psychology and the analysis of complex systems are of increasing relevance to the avoidance of error. These techniques have been incorporated into the Australian Incident Monitoring Program which developed in the anaesthetic forum but which has now been taken up by intensive care units and indeed hospital wide in many parts of Australia and New Zealand.