Bioconcentration potential of Ag, Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, Mg, Mn, Na, Ni, Sr, Pb, Rb and Zn by Pioson Pax (Paxillus involutus) fungus was investigated in field collections of mushrooms from 12 geographically distant sites in Poland. Caps, stipes and soil (0-15 cm layer) underneath to the fruiting bodies were examined. Inductively coupled plasma - atomic emission spectrometry (ICP-AES) was used to determine the total metallic elements content. Both "labile" (cold 20% HNO(3) extraction) and "pseudo-total" (cold and hot 65% HNO(3) extraction) fractions of metallic elements of soil were determined. K, Rb and Cu were effectively bio-concentrated by Poison Pax in caps and their BCF values were 1000 ± 520, 740 ± 540 and 100 ± 79, and less were Zn, Na, Mg and Ni with BCF of 40 ± 28, 33 ± 23, 18 ± 10 and 1.9 ± 1.4, respectively. Al, Ba, Co, Cr, Fe, Mn, Sr and Pb were bio-excluded (BCF < 1 in caps and stipes). The "labile" Ag, Cd and Hg content of soil was below detection limit of the analytical method. Ba, Ca, Mn, Na and Sr were more eficiently bio-concentrated in stipes of Poison Pax, while Fe, Mg, Pb and Rb in caps, and Al, Co, Cr, Cu, K, Ni and Zn similarly in caps and stipes. Also Ag and Cd (and Hg) were more effectively bio-concentrated in caps than stipes. Al, Ba, Fe and Pb were bio-excluded by Poison Pax (BCF < 0.2) but were abundant minerals of soil and more or less abundant also in carpophores. Some intermetallic relationships (co-uptake and binding) are evident for Poison Pax. The amount of "labile" fraction of metallic elements contained in soil doesn't seem to explain the Poisson's Pax accumulation potential for these elements. Biological features of species, which are related to its ability to enable, enhance or reduce uptake of metallic elements by mycelium and further translocation and binding in carpophores but in parallel also translocation to symbiotic plant can be major forces impacting amounts accumulated in caps and stipes. Metallic elements concentrations determined in fruiting bodies seem to explain in the best way what is largely bioavailable from the substrate in situ to a given mushroom species.