The communication is a specific activity of man and it is indispensable to the civilized structures. To communicate means to inform, to spread an informative content that contributes to the development of the other. The Church realized the power of mass-media, the services that these ones can bring for the Evangels spreading. The Second Vatican Council promulgated the Decree Inter mirifica through which points out the live nature of Church’s reality and the necessity to communicate it to the public opinion. The present article analyzes the historical context in which the document was published, its long term applicability and the enormous possibilities that the correct utilization of the mass-media offers.