This paper describes the mechano-synthesis of ZnS by high intensive milling of elementary sulphur and zinc in a planetary mill. Using complex physical and chemical methods (XRD, surface area measurement, IR and XPS) the probable occurrence of sphalerite was proved. The sphalerite was contaminated by iron (up to 0.14% of Fe) and the product of surface oxidation (hydrated ZnSO4). The reaction of mechano-synthesised ZnS with H2SO4 (170 g l(-1)) at 40-80 degrees C has a higher temperature sensitivity. A shift of the rate-controlling step to surface chemical control was observed, too.