Abstract: A method for the on-site determination of Al₂O₃, MgO, SiO₂, K₂O, CaO, Fe₂O₃, S, Cu, Mn, Zn, Bi, Sb, Pb, Ga, Ag, As, Sn in the polymetallic ores by Minipal 4 portable energy dispersive X-ray fluorescence spectrometer with pressed powder sample pellets has been developed. The method was tested by determination of these elements in national standard reference polymetallic ore samples and the results were in agreement with certified values with precision of 12%RSD(n=12). The method provides the advantages of simple operation, high efficiency and suitable for the on-site chemical composition analysis of ores in mine and in the field.