Ethylenediaminetetraacetic acid (EDTA) and nitrilotriacetic acid (NTA) are various applied as chelating agents for metal ions, then they are widely used in many industrial processes and domestic products. A method is described for the determination of EDTA and NTA in water samples by GC/MS . The reaction temperature, reaction time and pH for esterification of EDTA and NTA were investigated using 10% sulfuric acid-methanol, ethanol and propanol. Optimum conditions were obtained by the esterification in 80$^{C}$ for 1hr with ethanol. Method detection limits of ethylated EDTA and NTA in the 200 ml of water samples were 0.05 ng/ml, respectively, EDTA and NTA could be determined in the range of 0.05∼23.6 and 0.05∼7.0 ng/ml in treated water, and in the range of 0.06∼25.0 and 0.05∼6.40 ng/ml in raw water respectively. Risk assessments with EDTA and NTA exposure by drinking water ingestion were carried out. Based on the results of analysis, chronic daily intakes of EDTA and NTA would be less than the value of acceptable daily intake or tolerable daily intake.