This article carries out a cost benefit analysis of early childhood education for preventing reincarceration. It estimates the external benefits that accrue to society as a whole, in terms of the savings from specific crimes no longer taking place and the criminal justice system not having to be used, as well as the private benefits that are experienced by the prisoner, whose earnings stream can continue and who does not have to endure the loss of quality of life that being confined to prison generates. The costs are incurred in the past by an assumed preschool intervention that would have prevented school dropout and facilitated some college education. To estimate education effectiveness, life stressors are used as controls. The best estimate of the benefit–cost ratio was around six for some college component and it was over one for the drop out component considered alone.