The oxidation of benzene, toluene, ethylbenzene, and xylenes (BTEX) by advanced oxidation processes in water was investigated. The degradation of BTEX by UV-185 and UV-254 nm in conjunction with H₂O₂ was studied. It was observed that the recommended H₂0₂ concentration to degrade 100 mgTOC/L of BTEX was 250 mg/L and 300 mg/L for UV-185 and UV-254 nm, respectively. In addition, it was observed that using the lamps in series did not have any advantages in the TOC removal of BTEX. Under acidic condition, pH 3, UV-185/H₂O₂ removed 10% more than UV-254/H₂O₂. At the recommended H₂O₂ concentration, 90% of BTEX mineralization was occurred with UV-185 nm/HO₂ under acidic condition of pH 3. It was observed that 21-32% BOD/TOC ratio of BTEX was decreased with an increase in residence time (within 140 min) in the photoreactor.