Carbon dioxide and sulfur dioxide were simultaneously absorbed into aqueous 2-amino-2-methyl-1-propanol (AMP) in a stirred semi-batch tank with a planar gas-liquid interface within a range of 0-4.0kmol/m3 of AMP, 0.03-0.3 mole fraction of CO2, 0.005-2 mole fraction of SO2, and 298-318K. Absorption data of each gas in the CO2-AMP and SO2-AMP systems are obtained to verify their reaction regimes, based on film theory, respectively, which are used to analyze the simultaneous absorption mechanisms of CO2 and SO2 in the CO2-SO2-AMP systems. The measured absorption rates of CO2 and SO2 are compared to those formulated by an approximate solution of the mass balances with simultaneous reactions.