The main purpose of this study was to investigate mechanical properties such as the modulus of rupture (MOR) and compression strength parallel to grain (CSPG) of impregnated and heat-treated Oriental beech (Fagus orientalis L.) wood. Some copper and boron containing impregnation chemicals such as Wolmanit CX-8 (WCX-8) and Celcure AC-500 (CAC-500) were used. Wood specimens were impregnated 2% aqueous solution of the chemicals according to ASTM D1413-07e1 standard. The wood specimens were heated at 150 and 175 °C for 4 and 8 h, respectively. Results showed that both impregnation and heat treatment decreased the MOR and CSPG of Oriental beech wood. The MOR losses of Oriental beech after both treatments were higher than CSPG losses. The largest reduction of MOR and CSPG were observed with 51.5% and 15.5% for CAC-500 impregnated and heated at 175 °C for 8 h. Except for WCX-8 impregnation and heat treatment at 150 °C for 4 and 8 h, the MOR values of impregnated and heat-treated Oriental beech wood were lower than only heat-treated Oriental beech wood. It was also found that the CSPG values of impregnated and heat-treated Oriental beech wood were higher than only heat-treated Oriental beech wood, except for impregnation and heat treatment at 175 °C for 8 h.