Copper and boron based biocides are frequently used for wood preservation, their compounds being very effective at relatively low concentrations. Additionally, boron compounds have insecticidal properties as well. In spite of the relatively extensive use of copper and boron based preservative solutions, exact minimal remedial concentrations are not elucidated yet. The thesis tries to determine the concentration of boron and copper based aqueous solutions to inhibit fungal growth in infested wood. 3 brown rot fungi (Antrodia vaillantii, Gloeophyllum trabeum, Serpula lacrymans) and 3 white rot fungi (Trametes versicolor, Hypoxylon fragiforme, Pleurotus ostreatus) were utilized for testing. The results show that the curative efficacy of copper compounds is much lower than that of copper compounds. The growth of the great majority of the fungi tested is inhibited after submersion to aqueous solution of 5,000 ppm of boron. The highest tolerance against boron based biocides was determined at (Antrodia vaillantii). To prevent growth of these fungi in infested wood, the preservative solution containing 8,700 ppm of boron is required.