The use of peptide preparations is one of the current trends in modern agriculture. These preparations can be used to increase the efficiency of sowing treatment of agricultural crops seeds. The article presents the results of a laboratory experiment aimed at studying the effect of a complex of short peptides AC-3 (glutamic acid, aspartic acid, leucine) on seed germination and morphometric parameters of flax seedlings (Linum usitatissimum L.) - Tverskoy variety. The maximum germination energy (68, 68 and 74%, 50% at the control) and seed germination values (95, 95 and 100%, 75% at the control) were obtained in variants with seed treatment with a complex of short peptides at concentrations of 1*10-12, 1*10-13, and 1*10-15 g/l, respectively. According to the totality of the maximum values of seed quality indicators and morphometric characteristics of flax seedlings, the Tverskoy variety (the length of roots and sprouts, the yield of raw and dry biomass of seedlings), the optimal concentration of a complex of short peptides for pre-sowing seed treatment is 1*10-15 g/l.