143 soil samples representing 80 profiles (analyzed as soil paste extract) were taken from three districts in Kafr El-Sheikh governorate at North Delta, Egypt namely: El-Zawia (53 profiles),  Gharb El-Mansour (14 profiles) and Motobes (13 profiles) (during 2007 -2008). These samples were chemically analyzed representing the highly salt affected soils to hand out different purposes that accomplish some experimental objectives. The opportunity was seized through the chemical analysis of these samples and values of  sodium adsorption ratio (SAR) were calculated to modify, derive or fit the best fit equation representing the relationship between  SAR and exchangeable sodium percentage (ESP). The following empirical equation was fitted with the highest coefficient of determination among the other formulas: ESP = 1.8667+ 0.9228 (SAR) + 0.001 (SAR)²      (R²=0.9545) Statistical measurements such as: t-test, f-test chi-square test and correlation coefficient between the actual and predicted values of ESP using the current formula compared to the actual and predicted values of ESP using the own formulas of some other authors showed that the current formula significantly surpassed any other equation derived or modified before. The relationship between SAR and ESP with that formula and high coefficient of determination could safely and significantly enable to predict the values of ESP as soon as SAR values were calculated for the rotine work.