Ultrasonic velocity evaluated from Nomoto’s relation, Van Dael ideal mixing relation, impedance relation, Rao’s specific velocity relation and Junjie’s theory has been compared in the three binary mixtures of quinoline as a common component with o-cresol, m-cresol and p-cresol at 303.15, 308.15, 313.15 and 318.15 K over the entire composition range. A good agreement has been found between experimental and theoretical ultrasonic velocities.U2 exp/U2 imx has also been evaluated for non-ideality in the mixtures. The relative applicability of these theories to the present systems has been checked and discussed. The results are explained in terms of molecular interactions occurring in these binary liquid mixtures.