The article is dedicated to the problem of tolerance preservation under the conditions of national and cultural diversity of civil society on the example of the Republic of Mari El—a multi-ethnic region of the Russian Federation. On the basis of the analysis of earlier pedagogical and sociological research the ethnic, linguistic and confessional diversity of the Republic population has been described. The study of tolerance motivation of different population groups including teachers, students, experts, representatives of public authorities, civil society organizations and the mass media has been presented. A detailed description has been given to the most important conditions of the formation and tolerance manifestation in a multi-ethnic region: state policy and inter-cultural approach to education. The research has indicated that the present state of civil society in the Republic is characterized by the real inter-cultural tolerance being formed under the conditions of multinational diversity of the region due to the sensible politics of the regional government in social sphere, culture and education.