Tellurium samples in which current flowed parallel to thecaxis were irradiated at 78°K with 20‐Mev electrons. The conductivity increased linearly with a slope of 1.0×10−14(ohm‐cm)−1per electron/cm2up to at least 3×1014electrons/cm2. Beyond 3×1015electrons/cm2the slope was approximately one tenth of the initial value. The reciprocal of the Hall coefficient decreased at first and then increased. Between 1×1013and 5×1013electrons/cm21/RHincreases linearly from 3×10−5to 6.3×10−5coulomb/cm3. After irradiation, the samples showed no measurable conductivity changes during 14 hr at 78°K. After a day's anneal at 300°K the 78°K conductivity returned to its preirradiation value.N‐type germanium was irradiated with 20‐Mev electrons at room temperature. Conductivity measurements indicated that the sample became intrinsic and thenptype. However, the detailed dependence of conductivity on radiation dosage did not agree with a calculation based on four energy levels introduced into the gap. Carrier lifetime changes were also observed.