Solar photo-Fenton process is an attractive, alternative treatment technology among advanced oxidation processes for the treatment of wastewater containing recalcitrant compounds. The feasibility of solar photo-Fenton process for the treatment of pulp and paper mill wastewater was investigated in this study. The complete colour and chemical oxygen demand (COD) removal were obtained under optimal conditions, pH = 4, Fe2+ = 1 g/L, H2O2 = 5 g/L and irradiation time = 90 min. Also it enhances the biodegradability of wastewater and the biochemical oxygen demand (BOD3)/COD ratio was found to increase from 0.028 to 0.83. The effluent's BOD and total suspended solids concentrations were found to be 0 and 30 mg/L, respectively, which meets the requirements of the discharge standard. ? 2013 Balaban Desalination Publications. All rights reserved.