Weak property rights are strongly associated with underdevelopment, low state capacity and civil conflict. In economic models of conflict, outbreaks of violence require two things: the prize must be both valuable and contestable. This paper exploits spatial and temporal variation in contestability of land title to explore the relation between (in)secure property rights and conflict in the Brazilian Amazon. Our estimates suggest that, at the local level, assignment of secure property rights eliminates substantively all land related conflict, even without changes in enforcement. Changes in land use are also consistent with reductions in land related conflict.