This study analyses the recidivism-reducing effect of electronic monitoring (EM) in the context of early work release and home detention as a means of release preparation. We tested the hypothesis that EM reduces recidivism after the termination of EM. The results are based on a randomized controlled trial in Baden-Württemberg, Germany, where a pilot project between 2010 and 2012 enabled different forms of EM. The participating prisoners were randomly assigned either to the experimental group under EM or to the control group, whose participants had to continue their regular sentence behind prison walls. Qualitative data and data of a matched-pair sample complement the analyses. There was no statistical significant difference between the recidivism rates of the EM and control group subjects.