This article deals with a specific document base on the history of Evangelical Christians-Baptists in the USSR in the 1960–1980s, namely scientific-atheistic and propagandist literature. Employing several ideas of M.Yu. Smirnov and K.M. Antonov about the Soviet algorithm of work with religious material, the paper studies speech patterns and concepts which were used to interpret the activity of those Baptists who supported the Council of Churches of Evangelical Christians-Baptists. The adopted approach of source criticism allows us to disregard for the time being the issue of scientific value of the bulk of atheistic texts and to focus on those themes and plots that attracted attention of Soviet historians, sociologists of religion, as well as proponents of atheism who condemned supporters of church schism. The paper demonstrates that characteristic features of this phenomenon developed under the influence of political and legal evaluations of that time. Atheistic texts emphasised the illegitimate character of activities of Initsiativniki, blaming their authorities for anti-Sovietism and religious extremism. However, the Soviet treatment of Initsiativniki included a research dimension, due to which historical events were recorded and study methods of the schism within Baptism were enhanced. By the beginning of the 1990s, the Soviet antireligious discourse disappeared. The content of the terms “Initsiativniki”, “religious extremism” altered. However, if the name of Initsiativniki transformed into a historical term, religious extremism remains a concept imbued with negative connotations. The paper makes a conclusion about the topicality of critical study of antireligious discourse of the period from the 1960s to the first half of the 1980s.