Radio Frequency Identification (RFID) is a technology for automatically tracking the location of persons and objects tagged with a small radio transceiver. Its use in retail and security applications has received widespread attention in the popular press. RFID's application in hospital business processes is increasing rapidly, and a number of safety-critical clinical applications have been prototyped. In order to determine RFID's fitness for use in safetycritical as well as more mundane perioperative processes, the Operating Room of the Future project at the University of Maryland Medical Center evaluated six active-RFID systems. The evaluation consisted of hands-on testing of a variety of COTS systems employing the leading active-RFID technologies-802.11 RF, proprietary RF, ultra-wideband, infrared and ultrasound. In this paper we report the results of those tests and discuss their implications for the application of active-RFID technology to clinical applications.