Abstract: A method for impregnating wood, wherein the wood (1) is placed in an airtight impregnation tank (2) from which the air has been evacuated, and which is subjected to pressure after the introduction of the impregnating liquid (17). The impregnating liquid is introduced under completely airtight conditions, whereby the liquid (17) is devoid of gas and air when impregnation takes place. An apparatus for carrying out the method comprises an impregnation tank (2) for containing the wood (1), wherein the tank is provided with pipes connecting it to a storage tank (11) containing impregnating liquid (17) for supplying the liquid to the impregnation tank. In connection with the impregnation tank (2) and the storage tank (11), equipment for evacuating the air or other gas from the tanks, from the wood and from the impregnating liquid (17). In connection with the impregnation tank (2) equipment is provided for increasing the pressure in the tank, e.g.