The wet air oxidation of benzene has been studied in a 1.24 L stainless steel autoclave at a temperature in the range of 190-260 degrees C. The oxygen partial pressure was varied from 0.69 to 1.72 MPa. The initial C6H6 concentration was 5.63 mmol/L. The influence of the pH was studied, and the main reaction intermediates were determined. It was found that the temperature has a great influence on the wet air oxidation of benzene. The effect of the oxygen partial pressure was significant only at the beginning of the reaction. Decrease of the initial pH of the reaction results in a considerable increase in the benzene degradation rate, especially at the lower temperature. The main intermediates were found to be acetic acid and formic acid.