Locating building components that need to be worked on during maintenance tasks is critical for timely repair of the component and mitigation of the damage. The process of locating a component or a person in a facility is called indoor localization. The objective of this research study is to analyze the feasibility of three indoor localization technologies for supporting operations and maintenance (O&M) field tasks; namely, wireless local area network (WLAN), radio frequency identification (RFID) tags, and inertial measurement units (IMU). These technologies have been selected on the basis of the requirements of the localization needed for supporting O&M field activities. A previous work has been extended, which tested RFID-based locations in an indoor environment, by testing the three selected technologies in the same test bed and using the same hypothesis and fingerprinting approach developed in the previous work. The two main motivations behind using the same test bed and same approach are to have the same baseline to evaluate the performance of the three technologies and to evaluate the performance of RFID-based localization over longer periods. The results in the present study show that RFID-based localization suffers from a decrease in signal strength levels over several years, and that WLAN-based localization suffers from variations in signal strength. They also show that IMU-based localization suffers from drift in the sensors of IMU. Prior knowledge of the layout of a facility can improve the performance of WLAN, RFID, and IMU-based localization. DOI:10.1061/(ASCE)CP.1943-5487.0000177. (C) 2012 American Society of Civil Engineers.