The fungus Emmonsia crescens infection was detected (overall frequency 5.2%) in the Ore Mountains (Krusne hory) localities exposed for years to relatively high concentrations of industrial pollutants, largely sulphur dioxide. Infected species were Microtus agrestis (8.4% of individuals), Clethrionomys glareolus (4.8%) and Sorex araneus (0.9%). Localities with a heavy impact of air pollution harboured animals infected more frequently (6.7%) than those exposed to a light or moderate impact of air pollution within the same area (0.8%). Adults were infected more frequently (9.9% positive) than juveniles (1.5%).