The article is devoted to the study of technologies for the use of used motor and vegetable oils for hydrophobizing treatment of birch wood. In this work, synthetic and semi-synthetic engine oil is used to impregnate wood; spent corn oil, sunflower oil, organosilicon liquid GKZh-11, industrial impregnating composition of ZhTK. The effectiveness of the impregnating compositions is estimated by the indicators of water absorption and swelling in two mutually perpendicular directions (radial, tangential). Spent motor and vegetable oils saturate wood quite well and give it hydrophobic properties. At the same time, impregnation of birch wood with used engine oil (OMM) allows to improve water absorption of birch wood by 52.1% compared to natural wood and by 21% compared to water absorption. Thus, the processing of birch wood with used motor and vegetable oils makes it possible to utilize production waste and improve the properties of low-value wood species with a significant increase in its resistance to external influences.