Relevance. The wide use of extrusion for processing plant raw materials is explained by the possibility of improving the structure and increasing the availability of macronutrients of the target product. Extrusion of oilseeds is complicated by the negative effect of high lipid content on the ongoing physicochemical processes and, as a consequence, a decrease in the quality of extrudates. Along with their high lipid content, oilseeds such as flaxseed contain significant amounts of protein, soluble (mucilage) and insoluble (cellulose, lignin) fibers, which can also affect the technological properties of extrudates. As a high-energy and protein component, flax seeds are used in the feed industry. Increasing the nutritional value of flax seeds and their safety will expand the range of biologically active additives for the production of feed. The purpose of this work is to study the effect of extrusion on the feed value of flax seeds.Methods. For the research we used unmilled oil flax seeds produced in 2020. Flax seeds were processed by wet extrusion: the raw material was preliminarily moistened to 17% at 80 °C; extrusion process parameters — 120 °С, pressure 40 atm., duration 30 sec. Extruded flax seeds were obtained on a pilot plant of OOO “Fid-Group” (Belgorod region). Studies of extruded flax seeds were carried out on the basis of the laboratory for processing bast crops of the Federal Scientific Center for Fiber Crops (Tver).Results. A comparative analysis of the results showed a positive effect of short-term barothermal treatment, such as extrusion, on the chemical composition of flax seeds and their feed parameters. It has been shown that: the content of crude protein in extruded flax seeds increased by 3.97%, the water-soluble fraction increased by 66.18%, which indicates an increase in the biological value of the extrudate; the mass fraction of crude fiber decreased by 1.18%, which indicates an improvement in the digestibility of the extruded product; the content of mineral nutritional value increased by 12.5%; when using barothermal treatment, the nutritional value of flax seeds increased by 2.46%, metabolic energy increased by 2.19% and digestible protein increased by 4.08%; the level of indicators of the lipid complex, acid number and peroxide number, decreased by 40 and 39% respectively, which indicates a decrease in the activity of enzymes that cause hydrolytic and oxidative deterioration of the extrudate.