Kinetic studies of carbon dioxide absorption into aqueous potassium alaninate (PA) solutions were performed using a stirred-cell reactor at concentrations ranging from 1.0 to 3.0 M and temperatures from 293.15 to 313.15 K. In the present work, the potassium salt of alanine was suggested as an energy-efficient absorbent for CO2 capture. Densities and viscosities of the aqueous PA solution and physical solubilities of CO2 in the solution were also measured to evaluate the reaction rate constant. The reaction rate was determined as the following equation: -r(CO2) = 4.518 x 10(8)exp(-3845/T)exp(0.5706C(s))CsCCO2 (-r(CO2): rate of reaction between absorbent and CO2 gas [mol dm(-3)s(-1)]; T: temperature [K]; C-s: concentration of PA solution [mol dm(-3)]; C-CO2: concentration of CO2 in PA solution [mol dm(-3)]). Furthermore, the effect of the sterically hindered structure of PA was studied by comparing the diffusivity, physical solubility, and reaction rate constant with literature values of potassium glycinate.