The epiphytic lichen Parmelia caperata was used systematically as a bioaccumulator of radionuclides in the Travale-radicondoli geothermal held (central Italy). The results showed that radioactivity in this area is not different from that of other non-geothermal areas and that the exploitation of geothermal resources should not cause an enrichment in radioactivity. However, the survey also revealed a negative association between total beta radioactivity in lichens and the distance from geothermal power plants, so that the latter may represent a source of local radionuclide pollution.