Experiments on the plasma-assisted decomposition of dilute concentrations of methylene chloride in atmospheric-pressure N 2 and dry air streams by electron beam and pulsed corona processing are presented. This paper presents the first experimental evidence showing that the decomposition of methylene chloride in a non-thermal plasma at ambient gas temperature proceeds via reaction with nitrogen atoms. The decompositions is more efficient with energy deposition in electron beam generated plasmas because of the higher rate for electron-impact dissociation of N 2. In dry air mixture, the decomposition of methylene chloride is degraded substantially because the nitrogen atoms are consumed in the production of nitrogen oxides. At higher gas temperatures (300°C), the decomposition of methylene chloride in dry air is shown to proceed via reaction with oxygen atoms. The main products of methylene chloride decomposition in dry air mixtures are CO, CO 2, HCl, and probably Cl 2.