This work focuses on the experimental determination and thermodynamic modeling of the solubility of carbon dioxide (CO2) in an aqueous solution of 30 mass % 2-((2-aminoethyl)amino)ethanol (AEEA), with AEEA being a potentially new solvent for postcombustion CO2 capture by absorption. The vapor−liquid equilibrium (VLE) experiments were performed over a range of temperatures from 40 to 120 °C and for partial pressures of CO2 ranging from 0.01 to 220 kPa. The results obtained were then modeled by use of a modified Deshmukh−Mather thermodynamic model. The model provides a very good representation of the experimental data over the whole temperature range. In addition, 1H and 13C 1D NMR spectra were acquired for species identification and quantitative analysis of the major species distribution. The predicted speciation obtained from the model was also found to be in agreement with the speciation from the NMR data. Protonation constants (pKa) for AEEA were obtained by titration.