Here, the e ect of adhesion of CrN hard coatings on modi ed 42CrMo4 steel substrate is presented. Modi cations of the substrate are shot peening, nitriding, shot peening, and nitriding joined process. In the shot peening process, two variable process parameters were used: exposure time (t) and air pressure (p). e nitriding process was conducted in the following parameters: nitriding potential N p � 4.86, nitriding time t n � 3 h, and temperature process T � 530°C. Modi ed substrates were characterized by surface hardness HV5 and hardness pro les on the cross section of samples and by surface roughness parameters. On such prepared substrates, the CrN coating was deposited. e adhesion of CrN coating on modi ed substrates was de ned by the scratch test. Chemical and phase composition of the lms was determined using EDS method and X-ray di raction, respectively. e surface hardness of deposited lms was also de ned. e substrate of 42CrMo4 steel without mechanical and heat treatment coated by hard CrN lm was used as a reference.