The raccoon dog (Nyctereutes procyonoides) is a representative of Canidae and is closely related to red fox-like canids, although the species exhibits high distinctiveness in the family. These animals were farmed for fur products, but thousands were intentionally released into the wild in western Russia. This newly established alien species in Europe has spread rapidly into many European countries. The aim of the study was to determine the origin of Polish populations by comparing the mitochondrial molecular marker cytochrome b (cytb) sequences of Polish wild and farm individuals with wild raccoon dogs from the western Russia and Asian specimens whose sequences were obtained from GenBank resources. The results of our phylogenetic analysis support the previous suggestions on the existence of two main clades clearly referring to continental and Island populations. Polish individuals were classified into a highly diverse continental group. The relationships between the haplotypes within the clade together with estimated values of genetic diversity parameters indicate that the Polish raccoon dog populations exhibit high genetic similarity to the Russian population. In combination with the history of introduction of the species to Europe, this suggests the most probable assignment of the Polish populations to the subspecies N. procyonoides ussuriensis. Our results indicate the presence of two Japanese haplotypes within the continental group, which is inconsistent with the assumed scenario of post-glacial expansion of raccoon dogs excluding gene flow between continental and Island populations.