In this study, ozone pre-treatment was applied to spruce wood samples. Spruce wood samples at equilibrium moisture content (EMC) were pre-treated using ozone for 30 and 60 min, respectively. The intensity of ozone was kept constant at 15 g/h for all variations. The ozone pre-treated spruce wood samples were then impregnated with 2.5 % Alkaline copper quat ((Celcure AC500) (ACQ)) and 1% copper chromium arsenic (CCA) solution by applying initial vacuum for 20 min and then free-pressure for 30 min. The retention levels and penetration depths were determined for each variation and control sample. The ozone pre-treatment increased the retention levels and penetration depths. It was found that the retention levels were 5.03 and 5.27 kg/m3 for the ozone pre-treated (30 and 60 min) spruce for wood samples treated with 2.5% ACQ, while the retention level for control wood samples was 3.84 kg/m3. The results showed that ozone pre-treatment enhanced the impregnation properties of spruce wood. In addition, the applied ozone pre-treatment increased compression strength parallel to grain values (CS).