Technological innovations have changed the way many professions gather, store, understand, and disseminate information. Today, some of these same technologies are being used by correctional agencies to monitor and supervise offenders around the clock. A popular technological devise used in the supervision of offenders is electronic monitoring. Electronic supervision can be flexible and used in many ways. However, prior to using any technology tool, an agency must go through a needs and resource assessment process which entails a review of the available technologies to determine which form of electronic supervision will be most beneficial. This report presents and describes a number of technologies currently available and serving a variety of purposes in offender supervision. Electronic monitoring is just a supervision tool and in no way replaces the supervising officer. The success of an electronic monitoring program may be lessoned if the program does not have clear goals, if the supervising officer's caseload is too large, or if sanctions for noncompliance are not defined, readily available, and implemented when necessary.