The sulphatization roasting process for refractory copper-zinc sulphide raw material was investigated. The chemical and phase compositions of the investigated materials were studied. Thermodynamic calculations of sulphatization process for possible reactions were performed. The phase transformations, mechanisms of decomposition and oxidation of sulphide minerals were studied using DTA-TG analysis. Equilibrium distribution of the studied systems components during the copper-zinc sulphide raw material roasting was modelled using computer program HSC Chemistry 6.0. The optimum conditions for the roasting process in which sulphide minerals of copper and zinc pass into the sulphate form and iron into oxide one were established. The industrial test of sulphatizing roasting of copper-zinc sulphide middlings have con- firmed the results of experimental studies.