In this study the thermal conductivity of different wood materials was determined. For this purpose, Scots pine (Pinus sylvestris L.), Uludag fir (Abies Bornmulleriana Matff), Oriental beech (Fagus orientalis L), Oak (Quercus robur L.), and Chestnut of Anatolia (Castanea sativa Mill.) woods were used. In the test, the thermal conductivity of the woods was measured according to procedure of ASTM C 1113-99 standards. The lowest thermal conductivity was obtained in the perpendicular direction of Scots pine samples as 0.156 Kcal/mh degrees C. The highest thermal conductivity was obtained from perpendicular direction of samples in Oriental beech as 0.331 Kcal/mh degrees C.