Preventive detention legislation allows for the ongoing detention of an offender’s sentence. We explore the effects of pretrial detention on case outcomes in Bogotá, Colombia, from 2005–2017. Using pretrial judge leniency as an instrument, we find that pretrial detention leads to a 48 percentage point increase in the likelihood of being convicted. The rise in the probability of reaching agreements among defendants who would have otherwise been acquitted or had their charges dropped explains our findings. We also find evidence of an increase in the likelihood of pleading guilty for those detained pretrial and who experience a more significant incarceration sentence. Colombian prisons are overcrowded. Pretrial detentions add to the cost of maintenance of the prisoners. Policymakers should consider whether the costs associated with pretrial detention outweigh the potential benefits.