A study was made of the potential use of Acacia dealbata wood extracts as bio-protective agents. Initially, extracts were obtained from Acacia dealbata sapwood, heartwood and bark, and their antioxidant, antimicrobial and anti-quorum sensing activities were determined. Next, the decay resistance of Scots pine wood samples impregnated with these extracts was examined against the brown rot fungus, Coniophora puteana. The impregnation procedure was performed according to the ASTM D (1413) standard test method at two different concentrations, 3% and 5% by weight, using hot water and methanol as extraction solvents. The strongest antioxidant, antimicrobial and anti-quorum sensing activities were those of the bark extract. Hot water extraction led to lower performance than methanol extraction. According to EN 113 testing methods, the highest level of preservative effect against wood-decaying fungi was observed in the case of 5% methanol extract from the bark.