Heartwood and sapwood samples of Quercus laurina from Mexico were successively extracted with petroleum ether, acetone and methanol. The yield of the extracts from heartwood (sapwood) was 0,3 (0,1) % in petroleum ether, 1,9 (2,6) % in acetone and 2,5 (2,6) % in methanol. The extract were tested in vitro to determine their antifungal effect against three xylophagous fungi. The growth of Trametes versicolor was most strongly inhibited by the acetone extracts from heartwood and sapwood. The growth of Coniophora puteana was most strongly inhibited by the petroleum ether extracts from heartwood and sapwood. Finally, the growth of Chaetomium globosum was strongly inhibited by the methanol extract from heartwood and the acetone extract from sapwood. None of the three single extracts was capable of inhibiting the mycelial growth of all test fungi, showing that the decay resistance of Q. laurina  is based on a mix of active compounds.