A thermodynamic framework is presented for determining vapor-liquid equilibrium in carbon dioxide-methyldiethanolamine-water systems. Prediction of vapor-liquid equilibrium has been performed by a modified form of electrolyte-LCVM model. The model incorporates electrolyte NRTL model with translated modified Peng Robinson equation of state by linear combination of Vidal and Michelsen mixing rule. New electrolyte NRTL parameters are reported for the aforementioned system. The predicted results are in good agreement with experimental data and comparable to other thermodynamic approaches, for a wide range of temperature, pressure, methyldiethanolamine concentration and loading values. © 2016 The Authors.