Basing on the completed analyses of zinc and lead samples, which were collected from Olkusz-Zawiercie area, geostatic analyses were carried out and the most important mineral and chemical regularities and their changes were determined. According to the obtained results the author described the significant factors having an influence on mineralogy and chemistry of Zn and Pb ores. The occurrence of the mineralized zones was characterized in horsts and grabens area. Ore mineral composition and variability of dominant sulphides constans were shown in the paper. The particular attention was paid to galena and cerussite and their high contens in eastern and peripheric part of Olkusz region. Variability of Zn-Pb contens was estimated. It was shown that the shape of the cumulated curves and variability connected with sulphide ores mineralization are unlike to oxidized ores or to these ones which show the high level of lead mineralization. The most important factors having an influence on oxidation of sulphides were indicated as well as the conditions of ore pocket occurrence, variability of mineralization in horsts and grabens, hydrogeological conditions and the meaning of the hypsography of ore horizon were characterized. Moreover, the variability of oxidation degree for dominant sulphides in particular ores were also described. The attention was paid to variability of sulphide oxidation in Sikorka and Klucze which is different from this one occuring in other parts of the area. The oxidation degree of lead sulphides was analysed and on the ground of the analyses the cause of increase of cerussite content in Sikorka, Klucze and Olkusz ores were shown. There was presented the direct connection between oxidation of iron sulphides and depth of deposits. The most important regularity of ore quality changes were shown in the Olkusz area.