Several aryloxy acetic acids were synthesized under microwave irradiation. The factors, which affect the reaction, were investigated and optimized. It was revealed that the best yields(92.7%-97.4%) were obtained when the molar ratio of the reactants was n(ArOH) : n(NaOH): n(ClCH2CO2H) =1: 2.5: 1.2 with microwave irradiation power of 640 W for 65-85 s.