Carbon dioxide and nitrogen 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, 0.03-0.3atm of CO2, 0.005-0.2atm of NO2, and 298-318K. Absorption data of each gas in the CO2-AMP and NO2-AMP systems were obtained to verify their reaction regimes, based on film theory, respectively, which were then used to analyze the simultaneous absorption mechanisms of CO2 and NO2 in the CO2-NO2-AMP systems. The measured absorption rates of CO2 and NO2 were compared to those formulated by an approximate solution of the mass balances with simultaneous reactions.