Removal of contaminants such as acid gases, i.e. CO2, H2S, and sulfur components is the main step in a natural gas treatment process. In this study, the simultaneous solubility of carbon dioxide and ethyl mercaptan (ETM) in the different mixtures of the chemical and physical solvents are measured using a static high-pressure equilibrium cell at (328.15, 343.15 and 363.15) K within the total pressure range of (65-1235) kPa. The measurements are carried out for the three different blends of sulfolane-Nmethyldiethanol amine-water with the mass compositions of (10.0-40.0-50.0) wt.%, (20.0-40.0-40.0) wt.% and (20.0-30.0-50.0) wt.%, respectively. The solubility results are shown as the partial pressures of CO2 and ETM versus the carbon dioxide loading (moles CO(2 )per total moles of amine) and ETM mole fraction, respectively. The influence of sulfolane concentration is also investigated on the solubility of ethyl mercaptan and CO2 loading separately. Moreover, the influence of MDEA concentration as a chemical solvent is studied on the solubility of CO2 and ethyl mercaptan. By comparing the solubility of carbon dioxide in the same systems with/without the presence of ethyl mercaptan, it was found that the presences of ethyl mercaptan increases the carbon dioxide loading and by enhancing the gas partial pressure both the physical and chemical solubility intensify. Finally, using the Clausius-Clapeyron equation, the enthalpy of heat absorption for CO2 is calculated. (C) 2019 Elsevier Ltd.