Nanocomposites based on polypropylene (PP) and fullerene C-60 (in the range of 0.5-2 wt%) were prepared by melt compounding. It was observed that C-60 Could not only significantly enhance the thermal stability in nitrogen but also considerably delay the oxidation decomposition in air of polypropylene. Unexpectedly, the incorporation of C-60 greatly reduced the heat release rate of PP and resulted in a longer time to ignition. And the free radicals-trapping mechanism of C-60 was proposed for explaining the enhanced thermal properties and improved flame retardancy of PR Therefore, C-60 will be an effective flame retardant like carbon nanotubes and clay for PR (C) 2008 Elsevier B.V. All rights reserved.