Two hundred and three sera obtained in 1993-96 from red foxes (Vulpes vulpes), lynx (Lynx lynx), brown bears (Ursus arctos) and wolverines (Gulo gulo) in Fennoscandia (Norway, Sweden, and Finland) were examined for the presence of anti-orthopoxvirus antibodies by a competition enzyme linked immunosorbent assay (ELISA). High prevalences were found for the red foxes in Norway (7/62, 11%) and Finland (7/14, 50%). While only one of 73 (1%) lynx from Finland had anti-orthopoxvirus antibodies, a high prevalence was found in sera from the Sarek National Park in Sweden (5/17, 29%). In addition, anti-orthopoxvirus antibodies were found in one brown bear from the same area (1/45, 2%), whereas none of the 14 wolverines were seropositive. This is the first report of anti-orthopoxvirus antibodies in the brown bear and the lynx, and the first screening for such antibodies in Sweden and Finland. These results indicate that orthopoxviruses are distributed in Sweden and Finland as well as in Norway, and that the red fox and the European lynx may serve as indicator species for the presence of orthopoxviruses in the local populations of small mammals.