Five isolates of Wangiella dermatitidis from macroscopically asymptomatic bats were analysed by the agar-gel immunodiffusion tests and the mouse inoculation studies on virulence. No cross-reactivity among the antigens and antisera prepared from the bat and human isolates was observed. The fungus was shown to be neurotropic, of low infectivity and not implicated as a potential opportunistic pathogen. Differences in the antigenic composition and pathogenic potentials between isolates of the same fungus of different origins may reflect adaptation of the fungus in different hosts.