Densities, rho, and speeds of sound, u, have been measured for the ternary mixture {benzene + cyclohexane + hexane} and the corresponding binary mixtures {benzene + cyclohexane}, {benzene + hexane} and {cyclohexane + hexane}, at the temperature 298.15 K. Using these results, the isentropic compressibilities, kappa(s), the excess isentropic compressibilities, kappa(s)(E), and the speeds of sound deviations, Delta u, have been calculated for both the binary mixtures and the ternary system. Excess isentropic compressibilities, kappa(s)(E) and the speeds of sound deviations, Delta u, have been fitted to the Redlich-Kister equation in the case of binary mixtures, while the equation of Cibulka was used to fit the values relating to the ternary system. The empiric equations of Redlich-Kister, Tsao-Smith, Kohler and Colinet have been applied in order to predict the kappa(s)( )and Delta u of ternary mixtures from the binary contributions.