Tiwanaku influence significantly affected the lifestyle of the prehistoric peoples of the Atacama Desert as it represented an important period of social and economic change. Such intense changes as social stratification and new religious and ideological influences have always been characterized as peaceful ones. Palaeopathological studies based on the violence-induced traumatic lesions of 64 well-preserved human skeletons from an excavated funerary site named Solcor-3 have facilitated a comparison between Pre-Tiwanaku and Tiwanaku periods. Results show an increase in violence between males represented by low-intensity skull traumas, arrow wounds and a high mortality rate between 20 and 30 years of age during the Tiwanaku period. The interpretation of this data is contrary to the model of peaceful acceptance of the changes that followed the Tiwanaku influence into the Atacama. At least for Solcor-3, economic and political factors should be re-considered in order to explain the emergence of social tension during the Tiwanaku period. In the future, more detailed studies will probably help to clarify if conflicts had also extended to other sites in San Pedro de Atacama under Tiwanaku influence. Copyright © 2004 John Wiley & Sons, Ltd.