Armed conflict can endanger natural resources through several channels such as direct predation from fighting groups, but it may also help preserve ecosystems by dissuading extractive economic activities through the fear of extortion. The effect of conflict on deforestation is thus an empirical question. This paper studies the effect on forest cover of Colombia’s recent peace negotiation between the central government and the FARC insurgency. Using yearly deforestation data from satellite images and a difference-in-differences identification strategy, we show that areas controlled by FARC prior to the declaration of a permanent ceasefire that ultimately led to a peace agreement experienced a differential increase in deforestation after the start of the ceasefire. The deforestation effect of peace is attenuated in municipalities with higher state capacity, and is exacerbated by land intensive economic activities. Our results highlight the importance of complementing peacemaking milestones with state building efforts to avoid environmental damage.