[en] Highlights: • The solubility of CO₂ in aqueous LysK systems was measured. • Two models were used to correlate the solubility data. • The heat of absorption for LysK was estimated as about 55–70 kJ/mol. - Abstract: In this work, CO₂ solubility in aqueous potassium lysinate solutions has been measured for the concentrations of (1.25–3.28) mol·kg⁻¹ and at temperatures of (313–343) K. The vapour-liquid equilibrium data were correlated using a Soft model and a semi-empirical (SE) model. The proposed models can match well with the experimental data with AAD within 20%. The heat of absorption for LysK was estimated as about (55–70) kJ·mol⁻¹ CO₂ absorbed from the solubility data. The lower heat of absorption, compared with that of 30 mass% MEA, will be beneficial for the reduction of regeneration energy.