It was demonstrated that high speed switching of electronic ballast driven fluorescent lamp (EBFL) reflects and modulates the incident UHF RFID forward link reader- tag signal in a manner similar to that of modulated reverse link backscattered tag-reader signal. Qualitative analysis of EBFL's backscattered radiation properties indicated it has a half dipole pattern similar to that of the UHF RFID tag. Its backscatter signal spectrum falls within the spectral band of the tag signal with power levels exceeding that of a tag-reader signal power when located at distances over 5 meters from the reader antenna. Performance analyses results of an operating UHF RFID system, in close proximity to a set of active EBFLs, indicated without any doubt that the EBFL's modulated backscattered signal is a source of strong interference. It can compromise the reverse link and significantly affect the reception of modulated backscattered UHF RFID tag signals. The effects of this interference must be taken into consideration when developing an RFID system operating in an environment abundant with EBFLs.