The authors analyze legal, systematic, and organizational factors of extremist crimes, contributing to the onset of extremism in society, particularly on the Internet, offer the concept for their minimization, and propose a way to improve the counteraction to extremism. Materials and methods. In course of the research, the authors used general scientific methods of inquiry, as well as special scientific methods, such as interviewing, statistical method, comparison, procedures of generalization and interpretation of empirical data, etc. In preparing this study the authors used domestic works on criminology, criminal law, and criminal intelligence, records from the Centre for Counteraction to Extremism of the Interior Ministry of the Republic of Tatarstan, the National Anti-Terrorism Commission of the Republic of Tatarstan. The survey of the practitioners of the Centre for Counteraction to Extremism of the Interior Ministry of the Republic of Tatarstan played an important role in the findings. Results. Following the analysis of modern causes and conditions contributing to the spread of extremism, the authors conclude that the primary cause is the use of the Internet by the supporters of extremist ideology. Based on the results of the survey, the authors analyzed both the empirical data and identified problems. Discussions and conclusions. The analysis conducted by the authors allows to propose a number of theoretical and practical recommendations aimed at extremism prevention.