Pulse radiolysis was applied to investigate the reaction of C60(OH)36 with OH radicals or hydrated electrons (eaq). The second-order rate constants for the reactions between fullerenol and OH radicals (2exp9 dm3mol-1s-1) or hydrated electrons (2.5exp9 dm3mol-1s-1) were determined. The most probable mechanism of the reaction of OH with fullerenol was via the formationofa π-complext hat could dissociate to reform the reactants in competition with the rearrangement to the sigma-complex.The large number of hydroxyl groups attached to the fullerenol carbon cage did not result in any significant change in the rate constant for the reaction of fullerenol with hydroxyl radicals or eaq.