Ultrasonic attenuation and velocity are studied for edible oils over the frequency range 2-95 MHz at 19.4 C. Shear and compressional (volume) relaxation spectra are evaluated and compared. Viscoelastic (shear) contribution to attenuation is estimated by Rouse theory. The ratio of volume to shear viscosities decreases with frequency (except for castor oil), indicating that the shear and compressional relaxations are separated on the frequency scale. The results indicate that the molecular rearrangements in the compressional relaxation are long range and require a greater degree of co-operation compared with the shear relaxation. Possible mechanisms for the shear and compressional relaxations are discussed.