The present work studied, for the first time, the removal of organic pollutants from a high-salinity reverse osmosis (RO) concentrate by electro-Fenton approach using a graphite-felt as cathode. To gain insights into the process, the in situ generation of hydrogen peroxide was also investigated. The COD removal efficiency and energy consumption were optimized by investigating the effects of some important operating parameters such as ferric ion concentration, initial pH and cathodic potential. Under the conditions of cathodic potential at -0.72 V and Fe3+ concentration 0.2 mM, more than 62% COD could be removed in 3 h treatment, meeting the local wastewater discharge requirement (COD <50 mg/L). It confirmed the feasibility of electro-Fenton process for the treatment of RO concentrate accounting for its cost-effectiveness in wide pH ranges. (C) 2012 Elsevier B.V. All rights reserved.