The article is devoted to the problem of cultural relations between Poland and Russia in the second half of the 20th and early 21st centuries, which are studied using the example of musical culture and Russian-Polish relationships in the creative life of the St. Petersburg composer Sergei Mikhailovich Slonimsky. The significance of the genealogical and genetic roots and musical and creative contacts of the greatest master of modern culture with Poland and Polish music, both in the 19th and 20-2I-th centuries, is proved. It is concluded that it is musical culture, represented by its outstanding creative figures, that is capable, despite political differences, to establish strong, fruitful creative and friendly relations between the two Slavic countries.