Detecting and responding to security and privacy threats to Electronic Product Code (EPC) and Radio Frequency IDentification (RFID) technologies are becoming major concerns of information security researchers. However, and before going further in these activities, an evaluation of the threats in terms of importance must be done. We present such an evaluation. Our analysis of the threats is based on a methodology proposed by the European Telecommunications Standards Institute (ETSI). According to this methodology, we rank the threats to EPC networks in order of relevance. This assesment is intended to prioritize threats for future research on appropriate counter measure mechanisms.