The aim of this paper is to characterize one of the Atacama basin's representative populations of the Middle Period and the possible arrival of foreign groups associated to Tiwanaku expansion. The cranial collection from the Coyo Oriente cemetery, housed at the Museo Arqueológico de San Pedro de Atacama, was hence analyzed for its sex, age and intentional deformation patterns. These analyses were applied to the entire collection as well as to the three mortuary zones of the cemetery identified by Le Paige, that would represent a chronological occupation sequence. Further comparison between the two groups (one supposedly local, the other foreign) was achieved by means of the sites' textile component, as described by Oakland in 1992.