The decomposition process of melamine exposed to a high-energy electron beam has been investigated by monitoring the changes in the energy loss near edge structures (ELNES) using time-resolved electron energy loss spectroscopy. Calculations on different CN-containing molecules were performed in order to simulate the experimental ELNES observed at the different decomposition stages and to identify some of the intermediate compounds produced during this degradation process. As a result, we suggest that the amino groups are first eliminated as a release of N-2 gas. Then, the degradation of the molecule occurs through a reduction of the carbon-nitrogen double bonds. If the irradiation is maintained over longer periods, the formation of different CN fragments could then be possible.