A number of aminoamides of butanoic and pentanoic acids were obtained by the acylation reaction of N,N-dimethylaminoalkylamines. The activity of the synthesized aminoamides in the hardening reaction of commercial epoxy resin ED-20 was studied. Based on the data of differential thermal analysis and IR Fourier spectroscopy, as well as taking into account the content of the gel fraction in the hardened compositions, it was found that the activity of the hardener increases as the length of the hydrocarbon chain in the diamine fragment increases and the overall nitrogen content in the aminoamide molecule decreases. © 2023, Springer Science+Business Media LLC.