New parameters for improving the Electrolyte-NRTL model have been regressed for acidic gas-MDEA aqueous solution systems containing aromatics. Values of binary interaction parameters for liquid phase activity coefficients are estimated from regressions of experimental data. Aspen Plus has been used for regressions and thermodynamic modeling. The focus of the work is to have better predictions of VLE of aromatic compounds in amine systems for acidic gases purification.