Methyldiethanolamine (MDEA) solution is frequently used for the removal of acidic gases from raw natural gas. During maintaining, cleaning and scheduled inspection of absorption and desorption column of sweetening gas plant, a high concentration MDEA generated in the wastewater. This wastewater is toxic to bacteria and usually can not be treated using conventional biological treatment. Popular technique called Advanced Oxidation Processes (AOP's) such as UV/H2O2, Fenton's treatment and UV/Ozone has been used to treat the high concentration of organic contaminant in the wastewater. This study involves the UV/H2O2 advanced oxidation process to treat wastewater containing MDEA. Response Surface Method (RSM) was used to optimize the factor condition on MDEA degradation process. Approximately 85 of Total Organic Carbon (TOC) was removed. The biodegradability of partially degraded MDEA after UV/H2O2 was determined by calculating of the BOD5/COD ratio. The ratio increased after UV/H2O2 process. © 2012 Asian Network for Scientific Information.