The creative heritage of Zoltan Kodaly, an outstanding Hungarian composer and folklorist of the twentieth century, attracts attention with its deeply original national character, classical style and mastery of musical forms. However, often in the sphere of interests of musicologists, the analysis of his innovative musical and pedagogical system, symphonic and vocal music, prevails. Considering in this article one of the little-studied rarely performed Kodaly’s works - Sonatina for cello and piano-this paper fill the gap. Sonatina analyzed in a complex way: from the point of view of its formal structure, expressive features, style and musical language as such. The author also reveals the role and place of this composition in a number of other chamber and instrumental works of the composer in General and cello works in particular. Considering the stylistics of the Sonatina, we make generalizations about the nature of the evolution of the Kodaly’s musical language, from early instrumental compositions to significant symphonic and vocal-instrumental scores in the late period. Also discussed is the question of the relationship between vocal and instrumental principles in Kodaly's work and his preference for the cello, as an instrument that more fully and accurately conveys The specifics of vocal intonation than the violin – on which he began musical training in childhood. The analysis of harmonic features shows the proximity of Sonatina to folk origins, which is manifested in a particularly sensitive use of the possibilities of diatonics. Conclusions resumes inferences about the performance specifics of the Sonatina, its place in the concert and pedagogical repertoire. Conclusions emphasize the importance of this work for the formation of a unique compositional language of Zoltan Kodaly.