The solubility of CO2 in three different 1-butyl-3-methylimidazolium ([BMIM]) cation-based ionic liquids: 1butyl-3-methylimidazolium acetate ([BMIM][Ac]), 1-butyl-3-methylimidazolium chloride UBMIM][Cl]), and 1buty1-3-methylimidazolium methyl sulfate ([BMIMIIMeSO4]) was investigated. The CO2 solubility was determined by the measurement of the bubble-point or cloud-point pressure of the CO2 + IL mixtures. The temperature and pressure ranges were 303.15-403.15 K and 0.39-34.55 MPa, respectively. The results of this study show that the CO2 solubility in as were strongly affected by the different type of anions and also increased with pressure, and decreased with temperature. The sequence of magnitude of the CO2 solubility was [BMIM] [Ac] > > [BMIM][MeSO4] > [BMIM] [Cl]. For correlating the experimental data, we used the PR-EoS with one fluid mixing rule and the modified Lydersen-Joback-Reid method. The average absolute deviations of pressure (AAD-P) were 0.0335 for CO2 + [BMIM] [Ac], 0.0128 for CO2 + [BMIM] [Cl], and 0.0213 for CO2 + [BMIM] [MeSO4] systems.