Abstract: The aluminium tolerances of 12 ectomycorrhizal and 48 saprophytic fungi, mainly basidiomycetes were studied by cultivating aseptic cultures on MMN or ME solution to which aluminiun sulphate, potassium aluminium sulphate or aluminium chloride was added. Suillus luteus, S. variegatus, S. bovinus and Paxillus involutus grew in concentrations over 10 g Al+++/l. Species of Amanita and Trichloma were more sensitive. Saprophytic species (Mycena, Marasmius, Pleurotus) had in general much lower tolerance, concentrations of 100-250 mg Al+++/l being limiting. It is suggested that the high tolerance of mycorrhizal species can be regarded as an adaptation to naturally aluminiumrich conditions in acid forest soils.