Noncustodial sanctions may present an attractive way to reduce the prison population rate, but only when noncustodial sanctions meet custodial ones in terms of deterring recidivism. Using administrative criminal records data of all individuals convicted in the Netherlands in 2012, this study examines the effects of short-term imprisonment versus noncustodial sanctions on crime. We employ an instrumental variables approach to account for selection processes and to produce consistent estimates of the effects of imprisonment. Findings indicate that being sentenced to prison rather than a noncustodial sanction increases the prevalence of recidivism by 10 percentage points and increases recidivism rates by 1.07 registered crimes during a follow-up period of three years. Treatment effect heterogeneity analyses show that the detrimental impact of imprisonment is most pronounced for first-time prisoners, and adult offenders, compared to repeat prisoners and young adult offenders.