Since the 1970’s, the impressive fortified structures of the Cuyes river valley -located in the south of Ecuador, at the border between the Andes and the Amazonian lowlands-, have caught the interest of anthropologists and archaeologists: were these structures built and inhabited by Andean populations? Amazonian? when and in what kind of context? The dissertation aims at bringing new data to the debate through the use of a methodology of analysis of ancient ceramics totally new for the archaeology of the region, based on the concept of “chaîne opératoire” and on an anthropological interpretation of the material.