New experimental solubility data for carbon dioxide in pure water and in aqueous solution containing sodium hydroxide in the temperature range (293.15 to 393.15) K and pressures up to 5 MPa are presented in this work. A new experimental apparatus based on an equilibrium cell with a constant volume allowing the measurement of carbon dioxide solubility is presented. The liquid phase composition at the thermodynamic equilibrium is determined by an analytical method (ion chromatography) and a static synthetic method. The CO2 + water system is used to validate the experimental apparatus; therefore data obtained are compared with literature data.