Abstract Compositions of ashless thiophosphoric and thiocarbamine compounds were studied as a tribologically active additive. Studies of the anti-wear properties of compositions in both fresh and oxidized oil samples in comparison with the effectiveness of a similar functional effect of a traditional additive, zinc dialkyldithiophosphate, were carried out on a tribometer that implements the wear process of conjugated pairs under sliding friction conditions simulating the boundary lubrication mode. The results of tribotests of mixtures of these compositions with metal-containing detergents of various chemical nature in a solution of synthetic lubricating oil as model variants of the composition of engine oils are presented. The synergism of the action of the ammonium salt composition of dialkyldithiophosphoric acid and methylene bis-dibutyldithio-carbamate, which provides a reduced content of sulfate ash and phosphorus, factors of environmental safety of the use of oils, is noted.