Abstract It was specified that the combined optimisation of both surface hardening processes by means of vacuum carburising and final grinding with use of modern grinding wheels made of cubic boron nitride, led to synergistic generation of favourable compressive residual stresses within the surface layer. This is the advantageous spectrum of residual stresses from the bending and contact fatigue resistance of the gear wheels point of view. The methodology adopted and examples of residual stresses distribution by means of FEM method modelling are presented in this paper. Also, the original special equipment that allows the experimental determination of contact fatigue resistance of gear wheels and their bending fatigue strength is described.