Because prison overcrowding in the 1980's created an unprecedented need for alternatives to incarceration, interest in this option has increased. In 1987, at least 53 programs in 21 States were using some form of electronically monitored home confinement. In Illinois, two counties have implemented four such programs. All four programs use continuously signalling systems to monitor the arrival and departure of an offender at a particular location, 24 hours a day. All include strict eligibility criteria, use telephone lines for monitoring, and include a supervision component or other conditions of confinement. The programs are variously administered by the Sheriff's Office, the Department of Court Services, and the Probation Department. The individuals monitored in these programs include work releasees, pretrial releasees, intensive probationers, and other probationers. While these programs have been successful, the future effectiveness and potential of electronic monitoring of home confinement will depend on the resolution of related legal issues and an assessment of its financial and social costs and benefits. 17 notes.