In the last decades, new or amended national Constitutions in the Latin American and Caribbean countries have started to include ‘integration clauses’, which anchor at the national level the commitment of these States with regional integration. This article makes a comprehensive study of such integration clauses in all Constitutions in the region, using the theory of imperfect contracts as analytical framework. The paper analyses dimensions such as the clauses’ political principles and their geographical scope. We show that integration clauses reflect diverse political projects for the region and the richness of subregional idiosyncrasies, which crystallize in a mosaic of overlapping integration experiences. However, at the same time, variation with regards of integration clauses in national constitutions results in different degrees of completeness of the provisions, which points at a still imperfect articulation between the national and supranational levels.