Monoethanolamine (MEA) is commonly used in gas treating applications for scrubbing of acid gases and occasionally generated as a waste material with a high organic content. In this paper, the degradation of MEA solution in a UV/H2O2 advanced oxidation process (AOP) was investigated using a completely-mixed batch photo- reactor. The methodology of design of experiment using the Taguchi approach was applied to determine the optimum conditions and influence of various factors for efficient reduction of the chemical oxygen demand (COD) of the MEA solution under UV/H2O2 treatment for 60 minutes. Four factors at four levels were selected for the experimental design. The factors that were identified are UV dose, initial H2O2 dose, initial solution pH and temperature. The results indicated that UV dose and pH were the factors that had the strongest influence on the COD removal efficiency, although the effect of UV dose was much larger compared to other factors. COD reduction achieved in validation experiments conducted at the optimum conditions were compared with the results predicted by the Taguchi design of experiment methodology. The optimum process conditions for degradation of MEA were identified