In this article the author studies the correlations of the polyphonic (fugue, fugato) and homophonic (sonata) forms. As a result mixed, synthetic composition – polyphonic sonata, fugue-sonata appears. The author pays attention to some examples of this form in the works of the West-European and Russian composers of the XVIII-XX centuries . This subject is analysed more thoroughly on the examples of the chamber-instrumental works of the Georgian composers. In the ensembles of N. Gudiashvili, A. Shaverzashvili, S. Tsintsadze, R. Gabichvadze, N. Gabunia, K. Rosebashvili and V. Azarashvili the hybrid forms of the fugue-sonata are dealt with liberally according to the artistic intentions of the author.