The paper presents the results of examinations of the structure and mechanical properties of CrC+(Ni-Mo) type duplex layers produced by vacuum chromizing of tool steel surface covered with Ni-Mo alloy electrolytic coating. Investigations of layers thickness, their morphology, phase composition, hardness, depth profiles of elements in the layer diffusion zone have been conducted. For investigations of mechanical properties of these layers, the scratch test was used. It has been proved, that the adhesion of CrC+(Ni-Mo) type duplex layers to steel base is better than that of the CrC carbide layers, produced directly on the steel surface without any electrolytic coating.