Synopsis Low-energy (< 20 eV) electron processing of NH 3 multilayer films, systems of interest in astrochemistry, leads to significant NH 3 desorption, fragmentation, and to a complex chemistry arising from recombination and secondary processes induced by reactive products. Quantitative desorption rates of neutral species and effective cross sections for selected processes were obtained by combining three surface-sensitive techniques: High Resolution Electron-Energy Loss Spectroscopy (HREELS), Temperature Programmed Desorption (TPD) and Electron Stimulated Desorption (ESD) of neutral species.