Wooden objects of cultural and art historic heritage are priceless and should therefore, if attacked by wooden pests, be conserved in a safe and effective manner. However, by using unsuitable methods objects can often be exposed to great damage than pests. We have facused on the efficiency of asphyxiation on wood decay fungi with argon or nitrogen gas, in order to protect the environment and conservators, and to avoid possible damage of wooden arts. We examined the viability of wooden decay fungi: Coniophora puteana, Antrodia vaillantii and Trametes versicolor. The fungal survival was tested by respiration measurment via CO2 production and determination of hyphae growing on fresh PDA medium. The fungal cultures were exposed to low oxygen concentration (below 10 ppm) for 1-5 weeks in hermetically sealed vessels. Anoxic treatment did not affect the ability of regeneration of Trametes versicolor fungi on DPA medium. Fungus Coniophora puteana with the prolongation of anoxic conditions decreased the viability and by 16th week of treatment, 80 % of incocula did not regenerate. In 1st 10 weeks only 13 % of inocula of Antrodia vaillantii fungi cultures did not regenerate. However, by 16th week the percentage of unregenerated inocula increased to 77 %. Trametes versicolor cultures on samples of beech-tree, exposed to anoxic treatment in hermetically sealed vessels, did not lose viability, neither according to the type of inertive gas used nor according to the time of exposing to anoxic treatment. One third of Antrodia vaillantii cultures died in 2nd week of anoxic treatment with argon, while after 4th week, the time needed for regeneration increased. Antrodia vaillantii cultures exposed to anoxic treatment with nitrogen gas started to lose viability after 5th week of the treatment. In this time one third of them did not regenerate, while the other 2 thirds needed more time for regeneration. Coniophora puteana cultures on samples of spruce did not resume growth, neither within 1st week of treatment with argon nor within 2,3 or 5 weeks. It was found out that it is possible to suppress the infection with Coniophora puteana successfully. Treatment with nitrogen gas did not prove to be as efficacious because one third of Coniophora puteana in 3 weeks' time did not regenerate, while the other 2 thirds needed more time for regeneration.