This article explores the main problems pertaining to usage of mass media and the internet by terrorist organizations, as well as measures for prevention of their destructive activity on the web. Mass media greatly influenced the transformation of the nature of terrorism in the XXI century. In a paradoxical way the freedom of speech and expression, open access to information and means of information-communication technologies began to serve not only development of civil society, but also actively enable terrorist organizations. By publishing information on terrorist organizations and their leaders, the mass media practically proliferated their “political program” and through resonating illumination of the terrorist acts contributed to fearing of the population, creation of atmosphere of panic and fear. In the course of this research the author concludes that the problem of the usage of mass media and internet by terrorist organizations lead to the fact that even among the ranks of Western countries, which traditional advocated freedom of access to internet, free from censorship, attempts can be observed to limit the ability of terrorists to use the potential of mass media for destructive purposes. However, legislative limitations alone cannot solve the problem, since in the conditions of current level of technological development and access to the internet, virtually every user becomes the source of proliferation of certain content.