Incident Reporting is a tool for error analysis that has its tradition in high-risk industries such as aviation, nuclear power plants or the chemical process industry. The main purpose is to detect insufficiencies in the system as well as in the individual process of each enterprise. In medicine, incident reporting has only rarely been used for error analysis. Pioneering is the domain of anaesthesiology when it comes to apply this tool. In this report the method of incident reporting is described in general with its indications, requirements as well as its limitations. Furthermore a model for the definition of a critical incident in medicine is described and the first conclusions out of a national program of incident reporting in Switzerland are given.