The paper summarizes the main results of reach on heavy metal detoxification in ectomycorrhizas of Rhizopogon roseolus, Paxillus involutus, Cenococcum geophilum and Pisolithus arrhizus formed on Pinus sylvestris roots collected from heavily polluted areas in Poland. The data were obtained by methods including electron microscopy (TEM, SEM) accompanied by EELS and EDAX, cytochemical stainings and capillary electrophoresis. All of the species described in the paper are fungi highly resistant to toxic elements. As detoxification in mycorrhizas is dependent on both partners, the phenomenon was studied in fungi and in Pinus sylvestris roots. The strongest element-filtering effect was observed in R. roseolus / P. sylvestris symbiosis. This mycorrhiza type was characterized by the accumulation of heavy metals in the fungal mantle, and a gradual decrease of these elements was observed along the Hartig net towards the inside of the root. Potentially toxic elements were localized intercellularly in crystals deposited on the mantle and hyphal surface and in pigmented layer of the cell wall of the extramatrical hyphae, and the hyphae of the outer mantle layer. They were also detected intracellularly within electron-opaque depositions in the vacuoles. Much lower levels of toxic elements were detected in plant cells. The most common place for heavy metal accumulation was the phenolic material of the cortical cells.