The removal of Clopyralid (CLPYD) from aqueous solutions was performed by the electro-Fenton process in which hydroxyl radicals are produced electrocatalytically and used to degrade the persistent organic pollutants. The decay kinetics well fitted to pseudo-first order reaction and absolute rate constant of the oxidation reaction of CLPYD was determined as (4.4 +/- 0.2) x 10(8) M-1 s(-1). The oxidation intermediates of CLPYD were identified by HPLC and IC analysis. Based on these intermediates, a general oxidation mechanism was proposed in acid medium. Mineralisation ability of the system was followed by the chemical oxygen demand (COD) analysis. The obtained results showed that the CLPYD aqueous solutions were efficiently mineralised during the electro-Fenton treatment.