The reason of failure of many machine parts is contact fatigue. To increase contact-fatigue wear resistance it is necessary to create a surface layer possessing increased stress-strain properties which are formed by strengthening. The most effective methods of strengthening are those creating a surface layer with simultaneous high hardness and large reserve of plasticity. One of such methods is combined strengthening at which a surface to be strengthened is affected preliminarily by deformation shock waves forming a deep work-hardened layer and then its case hardening is carried out. As a result of this process a strengthened surface layer is formed which consists of hard uniformly strengthened carburized layer and a softer heterogeneously strengthened sublayer alternating hard and soft areas depending on streng-thening modes with shock waves. The operational researches of samples obtained by the offered combined strengthening have shown high efficiency of the method for life increase under conditions of contact cyclic loads which can increase considerably a range of machine parts to be strengthened.