In this paper a new method for measurement of absorption of ultrasonic waves in liquids is developed. Its main feature is a low frequency (L.F.) modulated ultrasonic transducer actuating a thin circular disk which is placed at some distance above it within the ultrasonic cell. The disk is suspended by a glass rod from a metallic reed which forms one plate of a small air condenser. The vibrations of the suspended system, which are resonant with the L.F. modulating component, are detected by a crystal controlled oscillator, working at the steep portion of its crevasse. The output of the oscillator is applied to a wave analyzer whose output gives directly a measure of the ultrasonic pressure on the disk.In a further development in the detecting end, a null method is used in which the reed is brought to rest by a L.F. balancing voltage supplied by the same modulator and the zero reading is adjusted by the aid of a cathode‐ray oscillograph.Two liquids are chosen for testing the apparatus, namely, benzene and water representing both high and low absorptive liquids, respectively. The values obtained are,2α/v2 = 16.2×10−16 sec2 cm−1for benzene, and2α/v2 = 52×10−17 sec2 cm−1for water, which compare favorably with the values obtained by the more elaborate pulse method. Moreover, the high sensitivity of the method eliminates all the complications which usually accompany high‐power ultrasonic beams.