Electronic monitoring was used with two groups of persons. The first group consisted of persons who were no longer eligible for community service because their offense was too serious or because of previous, unfinished alternative sanctions they received but who the judge wanted to keep out of prison. The second group consisted of prisoners who spent at least half of their term in a closed or a partially open prison and who were eligible for placement in an open prison or an institution for day detention. All candidates for the experiment had to satisfy certain demands: they had to have suitable accommodations in one of the four jurisdictions, with a telephone in working order; they had to consent to electronic monitoring; and they had to engage in work, study, or other activities outside the home for at least 20 hours a week during the period of electronic monitoring. In planning and implementing the electronic monitoring experiment, the probation service, the prison system, the judiciary, and the department of justice cooperated closely. One of the problems in the first year of the experiment was that procedures and possibilities of electronic monitoring remained unclear for many potential suppliers of candidates for electronic monitoring, such as judges, prosecutors, attorneys, and prison staff. This explained the relatively small number of candidates between July 1995 and June 1996. Another important bottleneck involved where to situate electronic monitoring in the Dutch prison system. Although several problems still had to be solved, results of the first experimental year showed electronic monitoring had the potential of substituting for part of unconditional prison sentences. Of 50 persons who participated in the experiment during the first year, only 2 did not finish their electronic monitoring. 8 references, 51 footnotes, 1 table, and 3 figures