Abstract: Examination of functionality of the genres of religious functional style is a relevant direction of modern linguistic research, which is substantiated by the change of social situation in Russia at the turn of the XX – XXI centuries, and thus, the growing role of religion as a form of public consciousness and a type of human activity. Sermon is a genre that functions in the Russian language, which makes it understandable and influential. The author applies the categorical-textual method, which gives an objective perspective and determines the characterological features of the genre, perceived as a type of similar texts with a standard way of explicating text categories; it also allows identifying the signs of invariant and outlining the transformative trends in the genre of sermon, substantiated by the new communication channels. The sermons delivered during liturgy belong to the core of the genre and feature predominant reverent tone, thematic duality: mandatory spiritual theme, with explication of situational and sacred themes, and reduced explication of profane theme; classical compositional structure, where the main theme is accompanied by spiritual interpretation, comprising a compositional complex, while the situational theme serves for creation of a circular plot. Sermons delivered outside liturgy are attributed to the mediated distant communication, which employs modern media channels: television or Internet, which substantiated a way of explication of textual categories that differs from the invariant. Non-liturgical sermons are classified as periphery of the genre and characterized by prevalence of the preaching, and at times aggressive tone, implementation of profane theme in the text, and reduced role of sacred and spiritual themes. Compositionally, non-liturgical sermons are noted for optional introduction and conclusion, with situational theme, which is explained by usage of modern communication channels. The categorical-textual method allows observing the transformation of the genre of sermon from the core towards the periphery.