To assess the repeated-dose toxicity of fullerene C60 by oral exposure, an OECD guideline test (TG 407) was conducted with administration of fullerene C60 at 0 (vehicle: corn oil), 1, 10, 100, or 1,000 mg/kg/day for 29 days in rats. No changes were observed in clinical observations, body weights, and food consumption in any treatment groups. Moreover, no treatment-related histopathological changes were found in any organs examined. Blackish feces and black contents of the stomach and large intestine were observed in males and females at 1,000 mg/kg/day in the treatment group. No significant changes in any organ weights were observed at the end of the administration period, but the only organ weights in liver and spleen in the 1,000 mg/kg/day group of male were increased at the end of the recovery period (14 days after the treatment period). The causal relationships between the possible absorption of fullerene C60 and those weight changes were suggested, but the pathological findings as indirect influences, such as swelling and congestion, were not also observed in the those organs. Using LC-MS/MS spectrometry analysis, fullerene C60 were not detected in the liver, spleen or kidney at the end of the administration period and also at the end of the recovery period. In conclusion, the present study revealed no toxicological effects of fullerene C60; however, with the prospective exposure by increased uses in future because of low toxic substance, more long-term exposure study is necessary to clarify the effects of fullerene C60 via oral exposure.