Solutions of C60 in toluene were investigated using Brillouin light scattering. The C60molar fractions for the solutions studied ranged from 0 (pure toluene) to 36 × 10−5(2.8 mg/ml C60 which is the saturation limit). The solutions were examined under a VV polarization condition and a distinct shift of the Brillouin doublets position was observed. It was found that adiabatic compressibility of the solution increases linearly as the C60molar fraction increases. Comparison to recently developed models predicting excess adiabatic compressibility in binary liquid mixtures is provided.