The degradation of sodium dodecyl benzene sulfonate (LAS), a common industrial and household anionic surfactant, has been investigated by electro-Fenton process. The electrolyses have been performed using an undivided cell equipped with a Ti/RuO2 anode and a commercial graphite-felt to electrogenerate in situ hydrogen peroxide and regenerate ferrous ions as catalyst. The effect of operating conditions such as applied current, catalyst concentration and initial pH has been studied. The experimental results showed that LAS was completely removed by the reaction with •OH radicals generated from electrochemically assisted Fenton’s reaction, and the decay kinetic always follows a pseudo-first-order reaction. The optimum experimental conditions has been obtained at I=200 MA, pH 3 and in the presence of 0.3 mM Fe2+ as catalyst.