Methyldiethanolamine (MDEA) as an organic material is a hazardous contaminant in the aquatic environment because of its adverse effects on aquatic life, environment, and humans. In this study, a batch reactor of ultraviolet (UV) light and peroxydisulfate was performed to investigate the degradation of MDEA in aqueous media. The effect of different experimental parameters such as UV irradiation, peroxydisulfate concentration, MDEA concentration, temperature, and solution pH on removal of MDEA was evaluated precisely. No significant degradation was observed with a separate UV light. Adding peroxydisulfate to the solution increased the removal performance more than 75 %.