Résumé : Populations concerned with mobile emergency care systems have the same age distribution in Leuven and in Brussels. Interventions for trauma are more frequent in Leuven and cardiac emergencies more frequent in Brussels, but these differences decrease when only critical patients are taken into consideration. The origin of calls is quite different in Brussels and in Leuven. The mobile emergency care system is underused in Brussels. The distribution of emergencies is influenced by the information and the formation of firemen, physicians and public.