Densities, p, and speeds of sound, u, of 2-propanone + aniline, + N-methylaniline, or + pyridine systems have been measured at (293.15, 298.15, and 303.15) K and atmospheric pressure using a vibrating tube densimeter and sound analyzer (Anton Paar model DSA-5000). The rho and u values were used to calculate excess molar volumes, V(E), and the excess functions at 298.15 K for the speed of sound, u(E), the thermal expansion coefficient, alpha(E)(P), and the isentropic compressibility, K(S)(E) at 298.15 K. V(E) and K(S)(E) are both negative magnitudes and increase in the same sequence: aniline < N-methylaniline < pyridine. The V(E) and K(S)(E) curves are shifted toward higher mole fractions of 2-propanone. The data have been interpreted assuming strong acetone-amine interactions and weak structural effects.