This study evaluates the effectiveness of the UV/H2O2 process in degrading ofloxacin in aqueous solution using a large photoreactor. The effects of UV wavelength, H2O2 dosage, and pH on the efficiency of degradation of ofloxacin were investigated. The UV/H2O2 process exhibited pseudo-first-order kinetics. The observed degradation rate constant (k) was determined under various operating conditions. The k value under UV-254 nm was 10.3 times that under UV-365 nm at an H2O2 dosage of 0.07 g/L and pH 3. The k value at pH 3 was 12.7 times that at pH 11 when the H2O2 dosage was 0.47 g/L. A larger H2O2 dosage was associated with a greater efficiency of degradation of ofloxacin. However, an excessive H2O2 dosage inhibited the degradation of ofloxacin. The efficiency of degradation of ofloxacin was 97% within 30 min at pH 3 using an H2O2 dosage of 0.27 g/L under UV-254 nm. Under the same conditions, the efficiency of mineralization of ofloxacin was 89% after 180 min. These promising results clearly demonstrate the potential of the UV/H2O2 process for the effective degradation of ofloxacin. (C) 2016 Elsevier B.V. All rights reserved.