We evaluate electronic monitoring as an alternative to prison for nonviolent offenses. Leveraging plausibly exogenous variation in sentencing outcomes generated by quasi-random assignment of judges, we find electronic monitoring reduces reoffending at both extensive and intensive margins. Compared with prison, electronic monitoring is estimated to reduce the probability of reoffending by 22 percentage points five years after sentencing and by 11 percentage points ten years after sentencing, with the cumulative number of offenses reduced by 40% ten years after sentencing. These results demonstrate that electronic monitoring has sustained crime-reducing effects.