The article discusses the phenomenon of radicalization, which becomes a source of danger for the individual and the security of the state. At the beginning the article discusses the essence and causes of the phenomenon, and then refers to the Polish and German strategies in the field of security. The documents identify radicalization and extremism as a contemporary threat to national security, which is confirmed by numerous attacks in Europe. Examples of attacks involving radicalized individuals are discussed in this paper in the article. The discussion ends with conclusions emphasizing that in the process of radicalization the information provided to individuals and communication between government institutions and society are extremely important.