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/m(3) at 241-345 kPa O-2 pressure (i.e., O-2 concentration range). The results show that MEA oxidative degradation depends on both the O-2 and the initial MEA concentrations, as well as the temperature, according to the intrinsic kinetic model -r(MEA) = 2.5 x 10(5)e(-(66 288.9/RT))[MEA][O-2](1.5). 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 O-2 imply that oxidative degradation of MEA is more sensitive to increases in the O-2 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.