Amine based sweetening process has been widely used for the removal of carbon dioxide and hydrogen sulfide from sour natural gas. However, during the process of absorption-desorption, a small amount of amine get carries over and discharged into the effluent wastewater stream. Treatment of amine wastewater using existing wastewater treatment plant (WWTP) without any dilution is very challenging due to its high Chemical Oxygen Demand (COD). However, dilution increases the volume of the wastewater and requires extension of the existing WWTP. Therefore, treatment of amine contaminated wastewater is a major concern for amine sweetening plants. Limited work has been done for treatment of amine contaminated wastewater, especially using membrane separation processes. The present study investigated the flux and rejection characteristics of methyldiethanolamine solution across composite polyamide reverse osmosis membrane (AFC99). The experimental work was carried out to investigate the effect of pressure, cross flow velocity and pH. The findings showed that AFC99 membrane was able to reject up to 99 of MDEA depending on the operating conditions. © 2010 Asian Network for Scientific Information.