The densities and ultrasonic speeds of ternary liquid mixtures were measured at 303.15 K. The mixtures were 1,2-dichlorobenzene + methyl ethyl ketone + l-propanol, + l-butanol, + l-pentanol, and + 1-hexanol. Isentropic compressibilities have been computed from measured speeds of sound and densities calculated from measured excess volumes. The deviation in the isentropic compressibility does not exhibit a regular trend in the four ternary mixtures.