The nonelectrolyte Wilson-nonrandom factor local composition model (N-Wilson-NRF) by Haghta-lab and Mazloumi is applied for modeling the vapor-liquid equilibrium of the acid gases (CO2 and H2S)-alkanolamine-water systems. The model is used to calculate the nonideality of species in liquid phase through the activity coefficient equations. In this work, we use the N-Wilson-NRF model for short-range forces in the aqueous electrolyte system of alkanolamines by using the concept of ion-pair. For the long-range interaction the Pitzer-Debye-Huckel theory is applied. The model is used to correlation of the solubility data Of CO2 and H2S in aqueous monoethanolamine (MEA), diethanolamine (DEA), methyldiethanolamine (MDEA) and 2-amino-2methyl-1-propanol (AMP) systems over wide range of temperature (0-140 degrees C). partial pressure (0.001-1000 kPa) and acid gases loading (0.001-1.0 mol gas/mol amine). To show the predictability of the model, the interaction parameters without any additional adjustable parameters are used to predict the solubility of CO2 in aqueous AMP solution at different conditions. The results of the model show a very good agreement with the experimental data. (C) 2009 Elsevier B.V. All rights reserved.