In a stand-alone fond ‘Astrakhan Gubernia Gendarmerie Department’ from the State Archive of the Astrakhan Region, there are several files concerning the history of the Muslim social movement in the Astrakhan gubernia in the period between the two Russian revolutions. According to statistical data, in 1900s Astrakhan ranked second in Tatar population, falling short only of Kazan. Then and there, as in other places, institutionalization and activation of the Muslim social movement was underway. But the Astrakhan Muslim community had several specific features due to its history. First of all, it was multinational. The cosmopolitan Muslim community, the mahalla, had its own nature, and that left its imprint on the social movement in the region. The gendarmerie agent took interest in all aspects of Muslims social activity in the region: cultural and educational organizations, secular education, periodicals. The gendarmerie materials described personalities and activities of prominent Muslim figures of the early 20th century, not just of the regional, but also of the all-Russian scale. The uniqueness of the document is in its information potential for studying the Tatar and Muslim national movement in the Russian Empire, its impact on the life style of the ethno-confessional enclave of the Astrakhan Muslims, and history of its relations with gendarmerie. The author examines factors that contributed to the creation of the document, analyzes historical facts and reliability of information on different subjects, provides some interesting information on the Astrakhan Muslim social movement of the early 20th century, its leaders, etc.