At the center of the article’s attention lies Nikolai Shabalin’s Chamber Music for Solo Button Accordion and Chamber Orchestra (1983), which is a significant for the musical culture of Udmurtia. Examining the peculiarities of the compositional organization of the Concerto, the author of the article makes the attempt to disclose the novel and individualized traits of the conception of this composition and at the same time for showing its continuity in regard to the traditions of the genre of the concerto for button accordion. Three main particular features of the Chamber Music stand out: the chamber music element, interpreted by the composer, first of all, as a subjective tone of utterance; the revision of the role of the soloist, leading toward a new type of interaction with the orchestra, in which the classical dialogic qualities yield to the tendency towards unification and unanimity; the one-movement form, in which the tendency towards through development is connected with cyclic features. The specificity of compositional structure is determined by the interaction of classical principles of form-generation (sonata form) and continuous evolutionism (a term of Vsevolod Zaderatsky). A great amount of attention is paid by the author to the meticulous thematic work of the composer, who projects the main intonational formula of the Concerto (perfect fifth – tritone) onto various musical levels. Shabalin’s Chamber Music demonstrates an organic combination of the traditional and innovative elements, which leads to a renewal of the genre of the Concerto for the Button Accordion. Keywords: composer Nikolai Shabalin, Concerto for Button Accordion and Orchestra, sonata form in the Button Accordion repertoire, composers of Udmurtia.