Methyl tertiary-butyl ether (MTBE) has been commonly used as a fuel additive because of its many favorable properties that allow it to improve fuel combustion. Unfortunately, increased production and use have led to its introduction into the water supplies. Accordingly, research studies have been initiated to investigate the treatment of contaminated water. Degradation of MTBE in aqueous solution by Fenton reagent (Fe²⁺ and H₂O₂) was investigated. This study used Fenton reagent to oxidize MTBE with an attempt to explore the behavior of MTBE decomposition and measure how factors such as pH, [H₂O₂] and [Fe²⁺] may influence the degradation of MTBE, and finally the optimum conditions were obtained. Under optimum conditions of 50 mL H₂O₂, 0.65 g/L Fe²⁺, pH=3-4 and room temperature, the initial 1000 mg/L MTBE solution was reduced by 99% within 120 min. The results showed that application of Fenton reagent was an effective method for degradation of MTBE.