We have investigated the kinetics of the acid-catalyzed hydrolysis of ethyl, propyl, and butyl acetates in aqueous binary mixtures of ethanol and of 1,4-dioxane without sonication and under ultrasound at 22 kHz. Various rate enhancements were found in the region from pure water up to 50 wt % ethanol and 60 wt % dioxane. The calorimetric measurements performed in the same region indicated an insignificant effect of the solvent composition on the ultrasonic power. It was concluded that the sonochemical acceleration of ester hydrolysis in ethanol-water and 1,4-dioxane-water mixtures may be interrelated with the destruction of the molecular structure of the binary solvent and essentially with the perturbation of hydrophobic solute-solvent interactions. The ultrasonic acceleration of polar homogeneous reactions takes place in the bulk reaction medium. This implies the presence of acoustic-field sonochemistry besides the generally accepted hot-spot sonochemistry.