In this paper we are interested in investigating the economic determinants for sustainable peace in post-conflict. To achieve the goal we selected a sample of countries, which after passing through internal armed conflicts, have managed to achieve peace. The large number of socioeconomic variables available in the databases analyzed involves using a methodology of principal components to choose those with the greatest explanatory power. In addition, a probabilistic model is constructed to determine which variables increase the probability of a sustaining peace. Our evidence suggests that the most important factors to get a lasting peace are: international aid, physical capital, infrastructure, technology, macroeconomic conditions and the added value of domestic production .