Five specimens of butoxysiloxanes were prepared and their tentative structures were proposed. Ultrasonic velocities were measured over the temperature range of 30 - 80-degrees-C using a multifrequency ultrasonic interferometer. Molar sound velocity, molar compressibility, adiabatic and isothermal compressibilities, inter molecular free length, internal pressure and free volume were computed using the experimentally determined ultrasonic velocity, density, specific heat, viscosity and molecular weight. Some of these properties were compared with the corresponding properties of tetraalkoxysilanes and polydimethylsiloxanes (silicones).