This article examines international interventions in the aftermath of civil wars to see whether peace lasts longer when peacekeepers are present than when they are absent. Because peacekeeping is not applied to cases at random, I first address the question of where international personnel tend to be deployed. I then attempt to control for factors that might affect both the likelihood of peacekeepers being sent and the ease or difficulty of maintaining peace so as to avoid spurious findings. I find, in a nutshell, that peacekeeping after civil wars does indeed make an important contribution to the stability of peace.