Phthalates have attained a great deal of attention recently due to their reported association with endocrine system disturbances. Currently, advanced oxidation processes (AO/RPs) are being considered for use in remediating these chemical contaminants from anthropogenic waste waters; however, there is little known about the kinetics of AO/RP radical reactions with phthalates in water. In this work we investigated the reaction kinetics of the hydroxyl radical, hydrated electron and sulfate radical with a series of phthalates and phthalate monoester metabolites using electron pulse radiolysis. A direct relationship was found between the molecular complexity of the phthalate esters and the natural logarithm of their corresponding hydroxyl radical rate constant. Phthalate monoester metabolites were found to have higher rate constants than the corresponding phthalate diesters of similar molecular complexity. No structural relationship was found between phthalate esters and their corresponding hydrated electron rate constant.