The effect o f steam ing on the durability against m icrobial degradation o f O riental Beech, F agus orierıtalis LIPSKY, w as investigated by exposing freshly cut boards outdooars, in a storage pile, for 7 m onths near Istabul after steam ing at 80°C for 21h, 42h and 64h together w ith the non-steam ed Controls. Steam ing for 64h resulted in 3.7 % reduction in density and 25 % reduction in im pact bending. Degradation during storage o f the 64h steam ed m aterial resulted in a 11.6 % reduction in density, and 94.2 % reduction in im pact bending. Storage o f the non-steam ed Controls resulted in 7.8 % reduction in density and, 57 % reduction in im pact bending. R esults obtained from boards steam ed for 21h and 42h and from visual grading o f the stored m aterial for their resistance to fungal growth w ere in agreem ent w ith these results.