Microwave current oscillations have been observed in uniaxially compressed n‐type germanium in high electric field. For the configuration where the current is along the  crystal axis, and the strain along the  direction, the effect is present at 27°, 77°, and 300°K. At 27°K, the oscillations begin at stress of 1500 kg∕cm2; the threshold electric field has a minimum of 270 V∕cm at a stress of 5000 kg∕cm2. These values are higher at higher temperatures. The phenomenon is believed to be due to the existence of a region of bulk negative differential conductivity which results from intervalley transfer of electrons between the stress‐split 〈111〉 valleys of the conduction band.