Abstract: Counterfeit electronic devices are detected by comparing a thermal profile of the counterfeit device and an authentic device under predetermined operating conditions. A thermal profile for an authentic electronic device is recorded executing an instruction set over time, such as with static infrared images at predetermined times, video infrared images over a predetermined time period or temperature measurements made at predetermined locations of the electronic device. In one embodiment, a thermal profile indicates that a processor device has been used in the place of a field programmable grid array device. In an alternative embodiment, an electromagnetic profile is detected instead of or in addition to the thermal profile. The electromagnetic profile of an authentic device is used to create an expected profile for comparison with an electromagnetic profile of electronic devices under test.