Minerals content (Fe, Ca, Mn, Mg, Na, K, Zn and Cu) of the leaves of Paraguayan yerba mate (Ilex paraguariensis, S.H.) as well as of commercial products has been determined by atomic absorption spectrophotometry. Considerable amounts of iron and calcium and remarkably high content of magnesium and potassium have been found both in the leaves and in the commercial products. Highly significant difference between the Fe content of the leaves and that of the commercial products has been found. Also, highly significant difference has been found between the Fe and Ca content of the higher quality-greater sale reputed commercial products and that of the lower quality-smaller sale reputed ones. Seasonal and soil linked variations are also presented. The nutritional and quality control significance of these findings for the MERCOSUR (Southern South America Economical Community) are discussed.