The solubility of CO2 in aqueous potassium salt of L-proline solutions has been measured in the temperature range of 285 and 323 K, for amino acid salt concentrations of 0.5, 1, 2 and 3 mol dm(-3) and CO2 partial pressures relevant to flue gas conditions, and up to 70 kPa. Precipitation was encountered in the system when absorbing CO2 in 3 mol dm(-3) potassium L-prolinate solution at 285 K. A beneficial effect of the solid formation on the overall CO2 solubility was observed. The vapor-liquid equilibrium data from the present work (for the non-precipitating regime) were interpreted by a concentration-based chemical equilibrium model. In spite of numerical simplicity of the model, a reasonable good description of the CO2-AAS-H2O systems could be observed. In the absence of literature data on equilibrium constant of the carbamate hydrolysis for L-prolinate, this parameter was calculated from the equilibrium CO2 solubility data. In addition, the enthalpy of absorption of CO2 in L-prolinate solutions was estimated using the solubility data, compared to that of monoethanolamine (MEA) and other common CO2 absorbents. Potassium salt of L-proline was found to be a promising candidate for CO2 capture. (C) 2012 Published by Elsevier Ltd.