The study challenges the essential facilities doctrine in theory and in practice. It has been present in the United States in regulatory literature and judicial and legislative practice since 1912, and it has been adopted in EU competition and sectoral regulation as well. The doctrine was devised for competition regulation, but it is becoming commoner for it to be cited in the regulation of network services as well. There have been numerous debates on its prospective role during the development of a new regulatory system for postal services - the last of the network services to be liberalized. The study begins by describing the main variant interpretations of the concept, before using the example of the United States to present the development of the doctrine and the change in its position in competition regulation. The differences over essential facilities in EU competition and regulation are explained in practice. The authors go on to look at Hungarian usage of the concept of essential facilities and to outline the debates and regulatory practices in the field of postal services.