In the present study, measurements on the solubility of CO2 based on the pressure drop method in mixtures of (choline chloride (ChCl) + glycerol) + L-arginine at various molar ratios (1:2:0, 1:2:0.1, 1:2:0.2, 1:3:0, 1:3:0.1, 1:3:0.2, 1:4:0, 1:4:0.1 and 1:4:0.2) were experimentally screened at 303.15 K and pressures up to approximately 20 bar. Based on the results of this screening, (ChCl + glycerol) + L-arginine mixture at 1:2:0.1 molar ratio exhibited the highest solubility of CO2 and further experimental measurements on the solubility of CO2 in this mixture were carried out at temperatures ranging from 303.15 to 323.15 K and pressures up to approximately 70 bar. The effect of L-arginine on the solubility of CO2 in ChCl + glycerol based DESs were observed. The results showed that L-arginine improved the solubility of CO2 in (ChCl + glycerol) + L-arginine mixtures. Besides, the solubility of CO2 increased with increasing pressure and decreased with increasing temperature. Henry's law constant, enthalpy and entropy of dissolution were calculated from the correlation of experimental solubility data. © 2016 Published by Elsevier Ltd.