Electrical discharge machining (EDM) is a well-established non-conventional machining process, used for manufacturing geometrically complex or hard and electrically conductive material parts that are extremely difficult-to-cut by other conventional machining processes. In EDM, the mechanism for removing material primarily turns electridtl energy into thermal energy through a series of successive sparks between the electrode and the work piece in a dielectric fluid. Therefore, topography and microstructure of an EOMed surface is complex and generally differs markedly from that to produce by conventional machining processes. This article presents tpe result of the investigation of surface performance of rocker die mold of the SKD61 hot work tool steel (surface roughness, surface microscopic hardness, microscopic structure of the surface layer, chemical composition of the surface layer) after electrical discharge machining with Cu electrode in oil dielectric.