The objective of this work was to determine the potential of fungi as agents for the bioremediation of wastes (particularly wood and soil) contaminated with quaternary ammonium compounds (QACs). Until now only bacteria have been investigated for this purpose. Tolerant strains of Gliocladium roseum and Verticillium bulbillosum were studied for their ability to degrade the following QACs: didecyldimethylammonium chloride, cocoalkyltrimethylammonium chloride, and dicocodimethylammoium chloride. Preliminary experiments were used to determine the toxic threshold concentrations for selected QACs in solid and liquid media. As solid media, wood and soil were treatet with the different QACs and inoculated with one of the fungi. After a pre determined incubation period, the QAC was extracted from the wood and soil samples and the loss of chemical was measured by HPLC using an indirect photometric detection. Both fungi were able to degrade considerable amounts of all QACs tested under the experimental conditions.