Two ionic liquids (ILs) namely bis(2-hydroxyethyl)ammonium acetate (bheea) and 1-butyl-3-methylimidazolium tetrafluoroborate (bmimBF 4) were mixed with water/aqueous solutions of monoethanolamine to form new hybrid solvents for the absorption of CO 2. The uptake of CO 2 in the aqueous mixtures of ILs+MEA were determined for a wide range of compositions at pressures between 100 and 1600kPa and at three different temperatures (298.15, 303.15 and 313.15K). For the case of aqueous (bheea)+MEA system, MEA acts as a supporting solvent whereas in the other case, (bmimBF 4) will acts as a supporting solvent for CO 2 capture. The effect of pressure and temperature on CO 2 loading for the aqueous solutions of bheea+MEA and (bmimBF 4)+MEA are discussed in detail. © 2011.