Nearly intrinsic germanium specimens were bombarded with H, D, He, Ne, and Ar ions of several energies between 20 and 140 keV at room temperature, and measurements were made at room temperature. Evidence was found for two kinds of annealing. The change of electrical conductivity as a function of depth from the bombarded surface was determined by stripping the surface with 3% H2O2 etching solution. The depth of the damage was surprisingly great and is explained as a peculiar radiation-assisted diffusion of interstitial atoms. On extended bombardment with Ne or Ar ions, a dip in conductivity appeared at a depth about that of the expected most probable range. For some specimens it was great enough to cause a maximum in the damage-dose curves.