The paper analyses the causes and determining conditions for the spread of extremist activities among Russian youth as well as the ways and means of preventing such crimes. The theoretical synthesis of a criminological approach and instrumental methods of conflictology allowed the authors to identify the following interpretations of the concept of "extremism": a circle of certain radical guidelines, ideas, theories; a kind of conduct that is socially dangerous; an aggregate of unlawful actions motivated by hatred. The authors outline the problems of legal understanding of extremism and its interpretation in law enforcement: 1) extremism is defined both as a type of activity whose goals contradict public norms and as a model of extreme behavior whose motives are quite legitimate outside the this model's framework; 2) the definition of extremism by its opposition to moral norms is impeded by the absence of a universal understanding of these norms; 3) labeling some participants of social relations as extremists could be politically motivated. The authors conclude that extremism can be interpreted both as an idea and as an action. The idea of extremism is a mechanical combination of different misanthropic conceptions. Extremism as an action taken in a situation of conflict is characterized by tremendous violence, disregard for formal and informal stereotypes of social conduct accepted in a society and rejection of compromise models of conflict resolution. It is shown that young people specifically are prone to taking extreme positions in case of conflicting interests and have a very acute perception of social reality. In societies with high living standards and multiple opportunities for self-realization this extreme behavior of youth is embodied in alternative subcultures. In societies with high levels of social tensions it takes criminal, violent forms, including extremism. It is important to incorporate soft power methods in extremism prevention and counteraction.