Experimental CO2 solubility data in brine at high temperatures and pressures are important for CO2 capture and storage (CCS) applications. Many data have been acquired in single-salt aqueous solutions such as NaCl, CaCl2, and Na2SO4. CO2 solubility data in aqueous solutions containing MgCl2 are extremely scarce. In this work, new experimental data of CO2 solubility in MgCl2 solutions were acquired. Thirty-three experimental points of CO2 solubility have been reported in an original range of pressure (1.5 to 20 MPa), temperature (323.15, 373.15, and 423.15 K), and salinity (1, 3, and 5 mol/kg). Measurements were made using the potentiometric titration method. Results show that the CO2 solubility increases with the evolution of pressure and decreases with the evolution of MgCl2 concentrations. A discussion about the salting-out effect on MgCl2 solutions is made, and a comparison is proposed on the same effect in aqueous systems containing calcium chloride.