The oxidation of phenol by Fenton's reagent was investigated in a medium suitable for bioremediation. An experimental design approach, based on a central composite rotatable design, was used to quantify the effects of H2O2 concentration (2000 to 5000 mg 1(-1)) and FeSO4.7H2O concentration (500 to 2000 mg 1(-1)). Performance of the chemical oxidation by Fenton's reagent was evaluated by determining the percentage of phenol oxidized at equilibrium. The analysis of variance test indicated that both H2O2 and FeSO4.7H2O concentrations had a positive effect on phenol oxidation. Hydrogen peroxide concentration was the dominating parameter for the removal of phenol by Fenton's reagent. The optimal concentrations of H2O2 and FeSO4.7H2O for complete oxidation of 2000 mg 1(-1) phenol in the medium were found to be 4340 mg 1(-1) and 1616 mg 1(-1), respectively, at 25 degrees C and pH 3. Oxidation of phenol in the culture medium was found to be significantly different than in pure water.