AbstractThe results of original research and published data on the number of alien parasite species of fish recorded in the Volga River basin are generalized. At present, 47 alien species of fish parasites are recorded for the Volga River basin. The problems of species status determination (native or nonnative) are discussed using specific examples. The species originating from the Amur River complex (33 species) dominate in the alien parasite fauna of fish in the Volga River basin. The Ponto-Caspian complex is represented by eight species. The ways of introduction of the alien species of parasites and possibilities of their naturalization in the Volga River are considered.