The oxidation of carbon nanotubes and nanoparticles has been studied by thermogravimetric analysis (TGA) in air. The maximum rate of weight loss took place at 695-degrees-C at a heating rate of 1-degrees-C/min. This result shows that the nanotubes and nanoparticles are more resistant to oxidation than other forms of carbon (diamond, soot, graphite, and C60) studied previously under identical conditions.1 The TGA of the nanotubes/nanoparticles in argon showed no weight change or detectable thermal transformation up to 1000-degrees-C.