The author examines social prerequisites of labor migrant involvement in the activities of organizations adhering to radical beliefs. The paper is based on a study carried out by a team of researchers form St Petersburg State University of Economics and St Petersburg University in two countries being the key donors of labor force for Russia, Tajikistan and Kyrgyzstan. The author identifies the social prerequisites for ideological radicalization of transnational migrants (i.e. favorable conditions to become an ideological radical) and analyzes public opinion concerning the radical groups in these countries. As an example the author uses the collected materials exploring the background of two conversions to radical groups. Taking into account the countries’ specifics, the paper considers the Salafi movement (banned in both countries) as a radical group. Thus, the author illustrates examples of conversion to Salafism from the more popular Hanafi Madhhab School of Sunni Islam, describes the social conditions of the conversion and the attitudes of the local residents towards this movement. Acknowledgment. The article was supported by the Russian Science Foundation, project no. 17-78-20107.