We examined the oxidative degradation of alkanolamines such as MEA, DEA, AMP, and MDEA. The oxidative degradation rate of the amines was in the order MEA > DEA > AMP = MDEA. The effect of oxidation inhibitors, EDTA and DTPMP, on the oxidative degradation of MEA was investigated and the products of oxidative degradation of MEA were analyzed. The oxidation inhibitors prevented the oxidative degradation of MEA and the extent of prevention was in the order EDTA > DTPMP. Among the products of the oxidative degradation of MEA in the oxidation condition, formate and acetate were the dominant degradation products, and EDTA and DTPMP decreased the products of oxidative degradation.