The optical limiting performances of the aqueous dispersions of multi-walled carbon nanotubols and [C60] fullerols were investigated using the Z-scan measurements at 532 nm. In addition, the optical limiting properties of nitric-sulfuric processed multi-walled carbon nanotubes and surfactant-assisted multi-walled carbon nanotubes in water, and C60 in toluene were also measured to make comparison. All the carbon nanotube materials used in our experiments, especially multi-walled carbon nanotubols, showed much better optical limiting performances than [C60] fullerols and C60. The mechanisms of the optical limiting performances of the samples were also proposed and discussed. (C) 2008 Elsevier B.V. All rights reserved.