Abstract The degradation of the p-coumaric acid (CA, 4-hydroxycinnamic acid) 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, initial CA acid concentration and initial pH has been studied. CA decay kinetic, the evolution of its oxidation intermediates and the mineralization of the aqueous solutions were monitored during the electrolysis by high-performance liquid chromatograph (HPLC) and Total Organic Carbon (TOC) measurements. The experimental results showed that CA 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 applied current, catalyst concentration and pH values were determined as 300mA and 0.3mM Fe2+ and pH=3. In these conditions, after 360min of electrolysis 95% of the initial TOC was removed, meaning the almost complete mineralization of the organic content of the treated solution.