Peace negotiations with left-wing insurgent groups have brought hope for a reduction in illegal economic activities in Colombia, including gold mining. We consider the impact of a transition to peace on possible trajectories of post-war crime in the gold sector, focusing on its major conflict-crime connections and responses by government authorities. We suggest that illegalities will likely persist, if not increase, in the post-war period given the challenges of consolidating Colombian state presence in mining areas, rapidly incentivising and assisting gold miners to formalise, and implementing stricter and more comprehensive due diligence measures in the mineral supply chain.