Using census data for Argentine prisons for the period 2002-2005, this pa- per presents evidence of the positive eect that prisoner formal education programs have on in-prison con‡ictivity measured as sanctions or violent be- havior of the prisoner. In order to overcome the problems of endogeneity that education decisions generate, we use an instrumental variables approach. Our results show a decrease in participation in violent con‡icts and bad behav- ior which can be partially attributed to the participation in formal education programs.