The experimental results of the equilibrium solubility of CO2 in aqueous 4-(diethylamino)-2-butanol (DEAB) solutions are reported over the temperature range of 298-333 K, CO2 partial pressure range of 10-100 kPa, and DEAB concentration range of 1-2.5 M. These results were then used to calculate, with the help of various thermodynamic models, the equilibrium solubility constant of CO2 in aqueous DEAB solutions as a function of various operating parameters. Subsequently, data for the chemical equilibrium constant that governs the CO2-DEAB-water reaction were fitted to the correlation models of Kent-Eisenberg, Austgen, Li-Shen, and Hu-Chakma and used to predict the equilibrium solubility as a function of temperature and CO2 partial pressure. The results show that these models did not represent the CO2 equilibrium solubility in aqueous DEAB solution very well, with absolute average deviations of 7.3%, 7.3%, 7.1%, and 8.3%, respectively.