Background. Surgical instrument retention and instrument breakage compromise surgery quality and lead to medical malpractice. We developed an instrument tracking system that could alert surgeons to instrument retention during surgery and monitor instrument use to reduce the risk of breakage. Methods. This prospective, experimental clinical trial included 15 patients undergoing inguinal hernia surgery or lumpectomy under general anesthesia at Saiseikai Kurihashi Hospital. Radiofrequency identification (RFID)-tagged surgical instruments were used, and a detection antenna was placed on a mayo stand during the operation. We analyzed the 1-loop detection ratio (OLDR)—that is, the capability of the antenna to detect devices in a single reading—and the total detection rate (TDR)—that is, the data accumulated for the duration of the operation—of the RFID-tagged instruments. Results. Data analysis revealed that the OLDR was 95% accurate, whereas the TDR was 100% accurate. The antenna could not detect the RFID tag when there was interference from electrocautery noise radiation, and 6% of instrument movement was undetected by the antenna; however, the TDR and instrument use were detected at all times. Conclusions. Surgical instruments can be tracked during surgery, and this tracking can clarify the usage rate of each instrument and serve as a backup method of instrument counting. However, this study was conducted on a small scale, and RFID tags cannot be attached to small surgical instruments used in complex operations such as neurosurgery. Further efforts to develop a tracking system for these instruments are warranted.