A detailed study has been made of the gaseous oxidation of triethylamine. At ca. 200 degrees C, the reaction has little autocatalytic character and there is a striking absence of surface-sensitivity and other features normally associated with gaseous oxidation processes. Under these conditions, the main reaction products are primary and secondary amines and acetaldehyde. Two distinct mechanisms appear to operate concurrently, one giving rise to ethylamine and acetaldehyde and the other to diethylamine and acetaldehyde; the latter process rapidly becomes self-inhibited as reaction proceeds. It is suggested that the former process involves unimolecular decomposition of intermediate peroxy-radicals, while the other reaction proceeds via the formation of the corresponding hydroperoxide. At higher temperatures, the autocatalytic character of the reaction increases, and the yields of simple products, particularly acetaldehyde, fall off sharply. The somewhat unusual results obtained at low temperatures may be ascribed largely to the powerful inhibiting effect which amines exert on gaseous oxidation processes. As the temperature is raised the observed behaviour resembles more closely that found in the oxidation of hydrocarbons, since the compounds responsible for inhibition are destroyed by secondary reactions.