A constant-volume method was used to measure the solubility of carbon dioxide in four mixed solvents at different temperatures and pressures. The mixed solvents are 2,3-butanedione + propylene carbonate, 2,3-butanedione + N-methyldiethanolamine (MDEA) + water, ethylene carbonate + MDEA + water, and acetoacetamide + MDEA + water. The data are compared with. literature data for the solubility of carbon dioxide in pure propylene carbonate or a mixed solvent of MDEA + water.