In the post-conflict situation in Colombia, it is necessary to improve the fiscal instruments that allow the sustainability of the territorial entities that have been affected by the armed conflict. This document presents the case study of the municipality of El Calvario, as an opportunity to propose mechanisms that consolidate a fair and efficient public revenue system, aimed at strengthening institutional policies and tax culture, based on the lessons learned in the international context. The findings suggest that El Calvario lacks the necessary fiscal effort to face the post-conflict, since the General Royalty System is not enough to cover this scenario given its complexity and the low institutional capacity of the municipality to design and implement projects. Nor is there evidence of a local tax regime that is consistent with the economic vocation of the municipality, nor a political dynamic that promotes effective collection.