The attenuation of longitudinal ultrasonic waves in single‐crystal germanium has been measured at several frequencies between 0.15 and 2.84 GHz in the temperature range 10°–60°K. The measured attenuation was the same for propagation in the⟨100⟩,⟨110⟩, and⟨111⟩crystallographic directions, and varied with temperature asT7at the highest frequencies and lowest temperatures, and asT3at the lowest frequencies near 60°K. The frequency dependence was less than linear at the lowest temperatures and between linear and quadratic at 60°K.