Anti-personnel landmines are one of the main causes of civilian victimization in conflict-affected
areas and a significant obstacle for post-war reconstruction. Demining campaigns are therefore a
promising policy instrument to promote long-term development. We argue that the economic and
social effects of demining are not unambiguously positive. Demining may have unintended
negative consequences if it takes place while conflicts are ongoing, or if they do not lead to full
clearance. Using highly disaggregated data on demining operations in Colombia from 2004 to
2019, and exploiting the staggered fashion of demining activity, we find that post-conflict
humanitarian demining generates economic growth (measured with nighttime light density) and
increases students’ performance in test scores. In contrast, economic activity does not react to
post-conflict demining events carried out during military operations, and it decreases if demining
takes place while the conflict is ongoing. Rather, demining events that result from military
operations are more likely to exacerbate extractive activities.