Radiation‐induced degradation in packaged bipolar junction transistors (BJT) can be efficiently removed by an anneal treatment carried out at 400 °C for 12 min in N2. The electrical characteristics of BJTs including current gain β, base currentIB, and collector currentICwere examined in the recovery of device performance. The radiation was performed by a Co‐60 (γ‐ray) source with the total doses ranging from 10 K rad to 10 M rad. The determinations of anneal temperature and anneal time were also discussed. It was shown that this anneal treatment did not degrade the radiation and hot‐carrier hardnesses of devices.