In 2006 I was a consultant on a CSL-funded project to investigate the return on investment (ROI) for library use of RFID as an item identification system. The study was completed but is no longer visible on the CSL web site, therefore I am posting it here. In addition, I am making available an Excel file that I developed (but never fully completed) that can be used to help libraries make an ROI estimate prior to purchasing an RFID-based system. (Licensed as CC-SA. See document properties.)