The influence of high gamma -ray doses and of annealing of radiation defects in antimony-doped germanium was investigated in the 1. 8-300 degree K range by measuring the electrical properties. The experimental results were analyzed using the theory of hopping conduction and percolation. It was concluded that bombardment of n-type germanium with gamma rays reduced the concentration of the donor states associated with group V atoms and compensated chemical donors by acceptors which appeared in the forbidden band of Ge.