Abstract: Polymetallic mineralizations around Mayıslar Village (Sarıcakaya-Eskişehir) are located in andesiticrocks of Eocene aged Meyildere Volcanites and in ultramafic rocks of Cretaceous aged Dağküplü Melangewhich is tectonically emplaced in the region. The mineralizations are formed at different stages andcaused alterations in the host rocks. Quartz and calcite veins intersect the altered andesites which aresilicified, seriticized, argillized and enriched by tourmalines. According to macroscopic and microscopicinvestigatons, at least two quartz generations as early and late quartzs (Quartz-I and Quartz-II) andcalcite formations together with and further than late stage quartzs have been determined. Ore microscopicstudies have revealed that in addition to oxide and sulfide minerals in the host rocks, sulfide minerals suchas pyrrhotite, pyrite, chalcopyrite, galena, sphalerite, fahlore and arseopyrite are determined.Fluid inclusion studies carried out on quartzs and calcites showed that Quartz-I generation exhibit theformation temperatures of 4700 - 3700 C and salinities of 27- 41% NaCl equivalent. Late stage quartzs(Quartz-II) and accompanying calcites with some exceptions between 3700 - 2700 C, display the formationtemperatures of 2700 -1100 C and salinities under 7% NaCl equivalent. Ore minerals seem to occur withlate stage quarzs and calcites.Considering together of alteration and ore minerals, tourmalines and fluid inclusion data strengthen thepossibility of a buried granitoidic intrusion. All these data indicate the reasonable view of siliceous,carbonaceous and ore bearing solutions moved from this intrusion due to tectonic activities as differentstages altered andesites and other country rocks and caused the formation of mineralizations.