We applied a recently developed scattering attenuation theory to model Q-values measured at the German KTB site and found that scattering attenuation plays an important role in the upper crust in this area. This does not conform with previous studies that suggest absorption mechanisms as the main reason for the attenuation. The scattering attenuation model used is based on the wave propagation theory in random media and allows quantification of scattering attenuation in complex geological regions using simple statistical estimates from well-log data. For our estimates of scattering Q we used statistical models of heterogeneities obtained from KTB logs. A good agreement between the magnitude of scattering attenuation and the measured Q-values shows the necessity of evaluating the role of scattering in seismic attenuation phenomena. ¿ 2001 American Geophysical Union