The microhardness variation as a function of strain has been evaluated on the base of the EBSD characterization of copper sample subjected to strongly inhomogeneous dynamic deformation. In order to fulfill the evaluation, the microhardness measurements as well as the microstructure analysis were performed at several locations along the direction of the strain gradient. The local strains have been determined based on the distribution of misorientations at deformation-induced boundaries. Mechanical twinning was shown to give significant contribution to the work-hardening under condition of dynamic deformation.