Surface modification of cold-working die steels aimed to enhance wear resistance and fatigue strength has been intensively explored by means of diverse technologies. The formation of a hard layer such as CrN, TiN, TiCN, etc. on tool surfaces has been widely utilized in machining tools. However, the hard layer has clear interface with the matrix, thereby the delamination between the hard layer and matrix often occurs because of a mismatch of the thermal expansion coefficients. Therefore, in this study, the formation of cemented carbide composite layer with complex interfaces with the matrix on surfaces of cold-working die steel (SKD11) by electron beam irradiation has been investigated. First, the influence of electron beam irradiation on the SKD11 surface was studied. After electron beam irradiation, a homogeneous processed layer was formed on the surface of the sample. Phase analysis and microstructural observations show that the processed layer is characterized by small dendritic structures with austenitic phase and no precipitations are found. Furthermore, in the processed layer, the hardness is improved from 200 to 430 HV. This hardening is most likely to be due to grain refinement and solution hardening of carbon and chromium atoms into the austenitic phase. Next, the formation of cemented carbide composite layer on the SKD11 surface by electron beam irradiation was undertaken. When WC-Co powder was embrocated onto the surfaces of samples, a composite layer of WC-Co and matrix was formed through solidification after the irradiation-induced melting. The composite layer shows a marble-like texture with WC-rich regions. The hardness of the layer reaches up to 1000 HV, however, it is revealed that there exists highly inhomogeneous distribution of WC particles on the irradiated surface. (C) 2014 Published by Elsevier Ltd.