Low energy electron attachment to the potent greenhouse gas SF5CF3 is studied at high energy resolution by means of mass spectrometric detection of the product anions. A large dissociative electron attachment (DA) cross-section forming SF5- + CF3 is observed within a very narrow energy range close to zero eV. In addition, comparatively weak resonances are observed near 1 eV yielding the fragment ions CF3-and F-. Some implications for the atmospheric lifetime of SF5CF3 and hence its global warming potential (GWP) are considered. (C) 2002 Elsevier Science B.V. All rights reserved.