The Late Intermediate Period in the Andes (A.D. 1000-1476) witnessed a decline in the prosperity associated with the Middle Horizon and the state of Tiwanaku (A.D. 750-1000). These disruptions are manifested in the construction of fortified sites, migration, and in a paucity of material culture. We investigate whether these changes affected the levels of interpersonal violence in the oases of San Pedro de Atacama, northern Chile. Nearly 150 crania from the Late Intermediate cemetery of Yaye, one of the poorest in the area, were examined for evidence of trauma. They demonstrated a very high frequency of cranial fractures, 29.2% of the population (42/144), distributed throughout the bones of the skull. These results were compared to contemporary sites, which show similar patterns. Moreover, crania from the Tiwanaku and Inka periods were also analyzed and compared to this data. The populations from these two periods show less evidence of cranial trauma than those from Yaye. In the Tiwanaku Period, 11.9% of the population is affected (11/92), but in the subsequent Inka Period we see a notable decrease in trauma (4.0% or 11/275). These temporal differences in trauma may be associated with the larger cultural changes in the area. The results of this study indicate the possibility that the high rate of trauma seen at Yaye is related to the stress of the Late Intermediate