The optical nonlinearities of C 60 /NH 2 (CH 2) 3 Si(OC 2H 5) 3 sol and gel excited by a Nd: YAG laser with 150 ps pulse duration, 1.06 μm wavelength and 1 Hz repeation were measured using Z scan technique. Theoretical fits from the data give the value of n 2=5.6×10 -12 esu for the sol and 6.2×10 -12 esu for the gel. In addition, the more higher laser transmission of the gel at the focus than that of the sol was attributed to the strong nonlinear scattering of the sol.