Schmorl's nodes are common lesions found on the vertebral column of ancient human populations. Their direct etiology is unknown, but common causes can be congenital weakness of the intervertebral disk and degeneration of the spine due to excessive biomechanical stress. This paper examines the prevalence of Schmorl's nodes in a prehispanic skeletal population sample (N = 97) from the Arica valley and discusses its distribution by spinal segment, sex, age and cultural period. Results show that an important segment of the population was affected throughout the cultural periods under study and that the frequency of the lesions decreases from the Archaic to the Late Intermediate Period, ranging from 39.1%, 30% and 23.8% respectively. This suggests that heavy spinal stress and an overall demanding activity pattern were present in the past and that some individuals carried out more strenuous, demanding tasks than others. The differences in spinal distribution during the Formative Period indicate that men were engaging in heavier activity patterns than women and the population as a whole.