The solubility (vapor-liquid equilibria) of carbon dioxide (CO(2)) has been measured in ionic liquids, 1-ethyl-3-methylimidazolium acetate ([emim][Ac]), 1-ethyl-3-methylimidazolium trifluoroacetate ([emim][TFA]), and a mixture containing a fixed mole ratio of 49.98 ([emim][Ac])/50.02 ([emim][TFA]) using a gravimetric microbalance at three temperatures (298.1, 323.1, and 348.1) K and pressures up to about 2 MPa. The [emim][Ac] strongly (chemically) absorbed CO(2) with hardly any vapor pressure above the mixture up to about 20% mole fraction of CO(2) at 298.1 K. The [emim][TFA] did not show the same behavior and physically absorbed CO2. The ionic liquid mixture containing equimolar amounts of [emim][Ac] and [emim][TFA] showed a combination of both chemical and physical effects, and the CO(2) solubility was well predicted at a fixed pressure using either a molar average of the pure component solubilities or a model based on linear isobaric lines in the ternary phase diagram. The binary pressure-temperature (PTx) data at 298.1 K have also been analyzed by use of an equation-of-state (EOS) model, and predictions at higher temperatures and of the ternary system are reasonable.