Speed of sound and densities were measured for N,N-dimethylformamide + methyl isobutyl ketone + 1-propanol, 1-butanol, 1-pentanol, and 1-hexanol at 303.15 K. Isentropic compressibilities and excess isentropic compressibilities from ideality were computed. Excess isentropic compressibility values are negative throughout the range of volume fraction in all four ternary mixtures.