In this study, it was investigated the possibilities of the use of fungal extract as wood protection solution against wood-degrading fungi. For that purpose, the decay resistance of Scotch pine wood samples, impregnated with Agaricus campestris fungal extract, was observed against the brown rot fungus Coniophora puteana. Impregnation procedure was applied at four different concentration levels and with two different extraction methods (hot water and methanol). The concentration levels were arranged as 1%, 3%, 5%, 7% for hot water and as 1.25%, 3.75%, 6.25%, 8.75% for methanol. The wood protective efficacy of extract solutions was determined by means of fungi decay test. The mass losses of the samples treated with both fungal extracts ranged from 3.53 to 20.91. The lowest mass losses in hot water (4.57%) and methanol extractions (3.53%) were seen in the samples treated at the highest concentration levels (7% and 8.75%). The wood samples impregnated at 7% and 8.75% concentration levels met the requirements of durability class 1 and were classified as very durable. Antifungal activity of methanol extract was stronger than that of the hot water extract. The variations which concentration levels were less than 7% did not have adequate protection to meet the requirements of the European norms.