Ultrasonic absorption in binary liquid mixtures containing benzene, chloroform, cyclohexane and toluene with triethylamine, a rotational isomeric relaxing liquid, as a common component has been studied at a frequency of 7.56 MHz. A pulse techrique has been used for the measurement of absorption with an accuracy of ±5%. Bauer-Sette formula has been used to calculate the absorption of these liquid mixtures at different concentrations. The theoretical values evaluated on the basis of Bauer-Sette theory appear to have good agreement with experimental values. In view of the discrepancy pointed out by Mallikarjuna Rao and Suryanarayana, the mixtures of benzene and ethylacetate have been studied in this context and found the theoretical values coinciding with experimental values.