Solubility of CO2 in aqueous solution of 40 mass % MDEA + 5 mass % AMP, 22.5 mass % MDEA + 22.5 mass % AMP, and 10 mass % MDEA + 35 mass % AMP at (313.15, 333.15, and 353.15) K and pressure from vapor pressure of solutions up to 2.5 MPa using isochoric saturation method (or volumetric–gravimetric method) were measured. The results showed that the CO2 solubility decreases with increasing of temperature and increases with rising of partial pressure of CO2 and also AMP concentration can improve absorption capacity of MDEA aqueous solution as [AMP]0/[MDEA]0 increases. Deshmukh–Mather model and Peng–Robinson equation of state were used for liquid and vapor phase, respectively, to correlate solubility data.