Twenty-five various ionic liqs. were synthesized and studied for biocidic activity against Basidiomycotina, Ascomycotina and Deuteromycotina wood-destroying fungi, fixation in Scots pine wood tissue and effect on phys. and mech. properties of the wood. The bis-quaternary derivatives of 1-octyldimethylamine and 1-decylimidazole nitrates showed the highest fungicidal activity. The adsorption kinetics of the ionic liqs. was described by the 2nd order model. Didecylmethylpoly(oxyethyl)ammonium propionate was recommended for practical use in wood-protecting formulations.