Information on chlorine concentration in groundwater for drinking and agriculture is important. If theconcentration of this element is in too much water can cause problems for humans and is toxic toplants. Measurement of chloride in groundwater is extensive, costly and time consuming. Find easyand inexpensive method has a special importance. the Statistical methods are based on spatialvariables. Changes of these variables point to the other have a certain continuity. This study forevaluation the ability of geostatistical methods for estimating chlorine using auxiliary variablesElectrical Conductivity in groundwater of Mashhad and the surrounding was conducted . For thispurpose, 276 wells were sampled and Parameters were measured electrical conductivity and chlorine.The data with software GS+ were analyzed. To determine the spatial correlation of data, Variogramswere calculated and plotted.The results showed good continuity exists between the measuredparameters. The correlation between two variables based on the variogram, 0 .91 Was calculated.Spherical model for Electrical Conductivity and Gaussian model for chlorine based on the minimumamount of RSS as the most suitable model was fitted to the data. For Comparison of methodsestimation of the root mean square error (RMSE) and plot of observational and estimated values wereused. Geostatistical methods, the chlorine more accurately than IDW and NDW methods wereestimated. پرونده مقاله