As objects of research, we used the products of processing of oil flax seeds of the varieties August, Isilkulsky, Legur, Sokol and LM-98, grown on the experimental field of the State Agrarian University of the Northern Trans-Urals, Tyumen (2020). Flaxseed cake is obtained by "cold" pressing of oil by pressing, extruded flaxseed cake by passing the previously obtained cake through the extruder. The amino acid composition was determined by capillary electrophoresis on an automatic amino acid analyzer of the KAREL brand. 14 amino acids have been identified, of which 8 are irreplaceable. The total amount of essential amino acids is higher in the Sokol and August varieties (linseed cake – 18.19 and 10.48%, extruded linseed cake – 9.92 and 7.29%, respectively). Of the essential amino acids found in flaxseed cake, the highest content differs: lysine (from 2.86 to 1.08%), phenylalanine (from 3.82 to 1.22%), leucine and isoleucine (3.88–1.49%) , valine (4.00–1.13%), threonine (2.30–1.52%) and, accordingly, in extruded flaxseed cake: lysine (from 1.60 to 0.72 %), phenylalanine (from 1.98 up to 1.06 %), leucine and isoleucine (1.96–1.08%), valine (1.93–0.912%), threonine (1.77–0.81%). The results obtained allow us to recommend extruded flaxseed cake for expanding the range of bakery and flour confectionery products.