The temperature dependence of emitter-base reverse stress degradation in bipolar transistors for Bi-CMOS circuits was studied. A suitable measure of degradation in the operating temperature range was chosen after careful consideration of the fact that bipolar transistor characteristics are very sensitive to temperature changes. The worst-case temperature conditions within the transistors’ operating range were determined. Degradation was found to be worst at around 50° C—a result of a tradeoff between thermal recovery from degradation and the effects of bandgap narrowing on bipolar characteristics. The recovery phenomena after degradation had taken place were also investigated in detail.