Abstarct: In recent decades protection and proper management of water resources in karstic aquifers has been considered because of their important role in providing drinking water. The purpose of this study is the investigation of the presence or lack of hydraulic connection between the Emam-Gheis karstic spring and drinking water wells of Shahreza. In this study, hydrogeology, hydrogeochemistery and isotopic investigations are done in the catchment area of Emam Gheis karstic spring and water wells. To determine the catchment area of Emam-Gheis spring firstly, according to geology and geomorphology conditions the probable catchment area was drawn. Then, according to hydrogeologic conditions and karst development, the penetration index was estimated at 60 percent. According to the volume of dynamic recharge of spring in this water year, which is estimated about 2.4 Mm3, primary calculated catchment area was corrected. To investigate spring and wells hydrogeochemical properties, their physicochemical properties were measured. Also for hydrogeochemical analyses, sampling were carried out 14 times from spring and seven times from wells. The results show that the electrical conductivity in spring is significantly lower than wells. Also, the major ion concentrations and ion ratios in spring and water wells show significant differences. Stable isotope analyses of spring and nearest wells water samples, sampled simultaneously, showed that the spring water sample is heavier than well water samples. Therefore, the ground water flow from spring toward wells seems unlikely.