Radio frequency identification (RFID) is a modern wireless communication technology used for identification purposes. By now, experimental results showing the actual performances reachable by a UHF RFID system, are still missing, together with the problems that can be encountered in practice and the corresponding solutions. In this paper, the performance of an UHF RFID system in real-world conditions are experimentally assessed to experimentally investigate the reliability of UHF RFID systems typical environmental conditions; and to deduce helpful and practical hints in order to efficiently assess and enhance performances of an UHF RFID system.