Simulators are more and more widely used in different scientific areas. Through very sophisticated and realistic simulations, they actually permit to teach and demonstrate theoretical or practical notions. Besides, they allow to evaluate a particular performance. In the latest years, the use of simulators has considerably developed in medicine. Anaesthetists have been the first to use and develop simulation. Having the possibility to deal with emergencies and getting accustomed to them without any real risk is an undeniable advantage. Even though the long-term effects due to a simulation session haven't been properly evaluated yet, it is important to bear in mind that simulators are being successfully used in an impressive number of centres in different parts of the world. The activities in the medical simulation centres deal to a certain extent with studying and teaching to manage critical events. This particular discipline, deriving from the aeronautic field, relies upon decision making and teamwork in order to manage the critical event most appropriately. Formative trainings, initially meant for anaesthetists and later on open to other medical categories as well, have been developed. Such courses aimed at establishing the proper interactions between different people with different tasks who are involved in the approach to an emergency rather than the management of the whole scenario. The main drawback of simulation is, however, the high costs required to set a simulation programme, especially as far as the human resources involved are concerned.