With deterioration of the electromagnetic environment, microcontroller unit (MCU) electromagnetic susceptibility (EMS) to transient burst interference has become a focus of academia and enterprise. Most electromagnetic compatibility (EMC) studies of MCUs have not taken the effects of aging into account. However, component aging can degrade the physical parameters of an MCU and change its immunity to EMI. This paper proposes a time-equivalent interval accelerated aging methodology combining DC electrical and high temperature stresses. The test results show variations in susceptibility to electrical fast transients (EFT) burst revealing increasing susceptibility. The reasons for MCU immunity drifts in the aging process are discussed. (C) 2016 Elsevier Ltd. All rights reserved.