Space or military electronic components are subject to both electromagnetic fields and total ionizing dose. This paper deals with the electromagnetic susceptibility of a discrete low frequency transistor subject to total ionizing dose deposition. The electromagnetic susceptibility is investigated on both non-irradiated and irradiated transistors mounted in common emitter configuration. The change in susceptibility to 100 MHz–1.5 GHz interferences lights up a synergy effect between near field electromagnetic waves and total ionizing dose. Physical mechanisms leading to changes in signal output are detailed.