Experimental CO 2 solubility data in brine at high pressures and high temperatures are needed in different technologies such as carbon dioxide storage or geothermal process. A lot of data have been acquired in single-salt solutions, whereas data for mixed-salt solutions remain scarce. In this study, new carbon dioxide solubility data in salt solutions have been measured. Two synthetic brines have been studied at 323, 373, and 423 K from 1 to 20 MPa. The brine 1 is composed of a mixture of NaCl and CaCl 2 and the brine 2 is made from a mixture of NaCl, CaCl 2 , and KCl. Measurements have been carried out by conductimetric titration. In this study, 6 isotherms presenting 48 new solubility data have been reported. These results have been obtained in an original range of temperature, pressure, and salinity. In these conditions of temperature and pressure, we verified that an increase of the temperature or the salinity involves a decrease of the CO 2 solubility. On the other hand, an increase of the pressure implies an increase of the CO 2 solubility. Then, the obtained results were compared with the values calculated using PhreeSCALE and PSUCO2 models. The comparison between experimental and calculated values revealed a good agreement.