Fullerene (C60) is a newly generated nanoparticle that has a soccer-ball structure with 60 carbon atoms. Fullerenes are expected to have a multitude of uses, for example as energy device materials or information technology materials. The biological effects of nanoparticles are now being discussed, and there are ongoing animal studies using various nanoparticles. Here we review some reports about the toxicity of C60, and in addition we present the results of our 2-year follow up studies of instillation and inhalation of C60 via the trachea.