White-Nose Syndrome (WNS) is an emerging devastating infectious disease which has already killed more than 5 million cave-dwelling bats in the Eastern territories of United States and adjacent part of Canada. The disease was named after the white patches on the nose, ears and wings of bats, caused by a psychrophilic fungus: Geomyces destructans. The infected bats wake up too often during wintertime, which depletes their fat reserves and the bats die before the end of the hibernation period. The fungus has already been recorded in at least 15 European countries, but no mass mortalities have been observed. Inoculation of North American bats either with American or European strains of Geomyces destructans severely affected the bats; this supports the novel pathogen hypothesis, that the fungus coevolved with European bats and its introduction into a naive ecosystem makes it lethal for the non-adapted hosts. The first documented occurrence of white patches on bats in Hungary was in an abandoned bauxite mine in Kislod, Bakony Mts. in February 2007. The authors sampled infected specimens from this mine and the fungus proved to be Geomyces destructans by PCR and also by microscopic observations. In this mine, infected specimens can be found every year. Since 2007, they have found Geomyces destructans in 10 other localities in five different mountains: 2 more findings in the Bakony Mts., 2 findings in the Mecsek Mts., 2 in Bukk Mts., 2 in Aggtelek Mts. and 2 in Pilis Mts. Three different species (Myotis blythii, Myotis myotis and Myotis dasycneme) infected with this fungus have been recorded in Hungary so far.