An investigation of the kinetics of the oxidative degradation of aqueous monoethanolamine (MEA) was conducted in a 300-mL autoclave in the temperature range 393-443 K and MEA concentration range 2-11 kmol/m3 at 241-345 kPa O2 pressure (i.e., O2 concentration range). The results show that MEA oxidative degradation depends on both the O2 and the initial MEA concentrations, as well as the temperature, according to the intrinsic kinetic model -rMEA = 2.5 × 105e-(66 288.9/RT)[MEA] [O21.5. This work represents the first attempt at both obtaining intrinsic kinetic data for the oxidative degradation of MEA and formulating a kinetic model that fits the data based on the initial rate. The values obtained for the reaction orders for MEA and O2 imply that oxidative degradation of MEA is more sensitive to increases in the O2 concentration than in the MEA concentration. It also shows that, even though our experimental conditions enabled us to model the reaction as a homogeneous liquid-phase reaction, MEA oxidative degradation itself is not an elementary reaction.