Ericoid mycorrhizal fungi can alleviate heavy metal toxicity to their host plant, but the mechanisms that lie behind this increased tolerance are unknown. As a first step in the characterisation of two isolates of Oidiodendron maius from mycorrhizal roots of Vaccinium myrtillus growing in heavily contaminated soils, we investigated their taxonomic position, their mycorrhizal capabilities and their ability to grow in the presence of heavy metals. When growth was compared with isolates from non-polluted soils, a better performance was observed in the presence of increasing concentrations of zinc salts, especially at higher ion concentrations. The mechanisms of tolerance may include the production of mucilage and extracellular pigments.