We discuss Chinchorro mortuary practices during the Middle Archaic (7000-5000 B.P.) as demonstrated by 12 funerary contexts excavated at the site of Maestranza Chinchorro, northern Chile. First we describe each of the funerary contexts. Then we discuss the variability of mortuary practices, the configuration of multiple burials, the mortuary treatment of human fetuses, lifestyle, and paleopathology. We conclude that mortuary practices are heterogeneous and that not all subjects received elaborate treatment. Mortuary ritual focused on the seven infants in the group, which included two fetuses of a few months" gestation, something fairly unusual in human prehistory. Treatment consisted in the removal of all soft tissue and the use of sticks to reinforce the skeletons, upon which abundant gray clay was mounted in order to model the human figure. In contrast to the infants, just one young adult woman received complex mortuary treatment. Finally, based on the spatial distribution of contemporary burial sites, we propose that Middle Archaic communities in coastal Arica comprised small groups, including adults and children of different sexes, that settled around key resources like watering holes, rivers, wetlands, and hunting and fishing areas. This resulted in fierce intergroup competition and highly territorial behavior.