One of the vectors of active search for genre solutions in the domestic musical and theatrical art of recent decades is associated with the mono-opera genre. It is characterized by extreme diversity and participates in the active processes of transformation of the opera, the pull for renewal and adaptation to the social, cultural and spiritual needs of society. The concert mono-opera «The Death of a Poet» by Sergei Slonimsky for voice and piano, considered in this article, is an example that largely preserves the traditions of monologue forms of utterance in the opera genre. Slonimsky’s opus reveals the theme of the Poet, the unrecognized prophet, which is relevant for contemporary authors. The appeal to M. Lermontov’s poem of the same name, ambiguous in terms of genre and semantic content, which combined elegy and satire, determined the specifics of the formation of the mono-opera, its stylistic diversity associated with the comparison of two main figurative spheres of the mono-opera – sphere Poet (Pushkin, Lermontov) and Socially (high society, Dantes). The mono-opera completely lacks stage action and storyline, which brings it closer to the vocal poem genre; the literary basis is completely preserved, the declamatory type of intonation prevails. The theme of the «archetypal» conflict is presented by the composer within the framework of romantic aesthetics: the image of the rebellious Hero with his lyrical impulses is opposed to the alien world of the Anti-Hero. Surveillance of the mono-opera by S. Slonimsky «The Death of a Poet» allows us to conclude that it largely inherits the fundamental properties of the genre, which consist in focusing on the experiences of a creative person who is in conflict with others, however, it sharpens such properties of the newest mono-opera as a monologue confession of the hero in a critical life situation, maximum concentration on the image of the protagonist.