Antiwear and extreme pressure properties of N-substituted 1,3,5-dithiazinane and 1,5,3-dithiazepanes obtained via the cyclothiomethylation of amines (monoethanolamine, propylamine) with formaldehyde and SH acids (HS, 1,2-ethanedithiol), taken in an amount of 3 wt %, in mineral oils have been studied.