A model is presented for the thermodynamic properties of the aqueous mixture of carbon dioxide, up to 30 mol% composition, in a large range of temperatures (400–1000 K) and pressures (0–100 MPa) around the critical point of water. The model for the Helmholtz free energy of the mixture is based on the principle of generalized corresponding states, with the NBS/NRC Steam Tables as the reference state for pure water. Input to the model are data for the critical line of the mixture, apparent molar volume andpVTxdata in supercritical water, phase boundaries, excess enthalpies and mixture second virial coefficient data. Comparisons are presented with those data, with Henry’s constants and with other formulations available for this system. Phase boundaries and tabulated values of molar volumes, enthalpies, and fugacities are presented along 35 isobars from 0.05 to 100 MPa, for four compositions,x=0.05, 0.10, 0.20, and 0.30, respectively, at 19 temperatures in the range of 400 to 1000 K. For the same pressures and temperatures, we also list the infinite‐dilution (standard state) properties: partial molar volume, enthalpy, heat capacity and fugacity coefficient of the solute CO2. The Fortran codes for generating these properties are listed in Appendix B.