: Recent advancements in wireless technology have resulted in an unprecedented demand for Radio Frequency (RF) spectral resources. Increasing frequency reuse also increases RF interference, which decreases a system's capacity and/or service quality. The primary focus of this research was the development of a test protocol for the characterisation of the performance of Radio Frequency Identification (RFID) systems when active interference was present. The test protocol was comprised of four different experiments: Jamming on Central Frequency of Operation, Apply Full Range of Frequencies in Sweeps, Modulating the Jamming Signal and Tag Pollution. The effectiveness of the test protocol was verified by fully characterising eight RFID systems operating at frequencies that ranged from 120 kHz to 2.45 GHz. The performance measure of read rate was utilised to assess whether or not the jamming signal had an effect on the performance of the RFID systems. The results obtained through actual experimentation, as well as the validation by experts in the RFID field, indicate that the approach described in this research is viable and useful for both manufacturers and users of RFID technology. © 2006 Inderscience Enterprises Ltd.