Measurements of the ultrasonic attenuation and relative velocity changes of longitudinal waves of frequencies between 5 and 25 MHz are reported for clear yellow Dominican amber at low temperatures. Between 4 and 130 K the attenuation and velocity change are glasslike in their temperature and frequency dependencies. At higher temperatures both properties seemed to be affected by the &agr; or &bgr; viscoelastic relaxations. Similar ultrasonic behavior is reported for commercial polymethylmethacrylate. Our results at low temperatures compare well quantitatively with data of other organic and inorganic glasses, except for the stronger logarithmic frequency‐dependent velocity change which is observed for both materials.