Two strains (UB-1 and UB-2) of rabies-related viruses were isolated from the brain of Nyctalus noctula and Vespertilio murinus captured from the hollows of tall trees on the left bank of Pripyat river in the Volynsky region of Ukrainian S.S.R. The viruses were isolated by means of intracerebral inoculation to white mice. The isolates were identified as rabies-related viruses of Duvenhage type in an indirect test of fluorescent antibodies with the panels of nucleocapsid monoclonal antibodies (NC Mab) provided by Wistar Institute (Philadelphia) and by Central Veterinary Laboratory (CVL, Weybridge). During the typing with the Wistar panel of NC Mab complete antigenic similarity was established between the newly isolated strain and Yuli virus. The reaction with CVL NC Mab revealed group-specific antigenic similarity between Yuli virus on one hand, Duvenhage-6 and Duvenhage-66 on the other hand, as well as between UB-1 and UB-2 and Duvenhage-26. The reaction with antibodies to clones DB-3,4,6,9, and 10 detected antigenic similarity between the viruses of chiropteric origin isolated in the U.S.S.R., North-West Europe as well in Africa, although some differences were discovered. Yuli, UB-1, and UB-2 viruses isolated in the U.S.S.R. were proved to belong to Duvenhage group of viruses (serotype 4).