In this study, the effect of heat treatments on the microstructure and wear resistance of Hadfield steel with different Cr + Ni contents is investigated. Hadfield steel with 1.2% wt. C and 12% wt. Mn is melted in an electric arc furnace. Added elements (Cr and Ni) are crushed and added as ultra-fine powders of ferro-alloyed composition in a well heated ladle. Two series of heat treatments are applied: one at 1100°C and the other at 1050°C. The microstructure of these steels is analysed using optical microscopy, scanning electron microscopy and X-ray diffraction. The Rockwell C hardness and the Vickers microhardness are measured at ambient temperature. The wear behaviour of all samples in as-cast and heat treated states is studied using pin-on-disk wear tests. The obtained results show that the microstructure of the as-cast Hadfield steel samples consists of an austenitic matrix and complex carbides precipitated at the grain boundaries. Increase in the Cr + Ni content refines the structure that improves the hardness and the wear resistance. In the heat-treated state, the microstructure reveals two distinct phases: martensite and retained austenite. The increase of heat treatment temperature favours the martensitic transformation, which positively affects the hardness and wear behaviour of studied steels.