The study presents results from investigation of tribological properties demonstrated by nitrided layers developed on 18HGT and 38HMJ constructional steels with use of the controlled gas nitriding. Tribological properties of these layers were assessed by means of the cone-three cylinder method. It was revealed that application of the gas nitriding process to samples of 18HGT and 38HMJ constructional steel grades significantly improved their resistance to friction wear.