An unusual case of discontinuous hard tissue hyperostosis is described in a 25-30-year-old female dating between 4000 and 5500 BP from northern Chile. This specimen was one of 104 individuals examined from the Morro-1 site, which is known to represent the Chinchorro culture. The only other reported case from antiquity dates to 500 AD (Lester [1969] J. Bone Joint Surg. [Am.] 49:142-143). A review and comparison of this case to the medical literature supports a diagnosis of melorheostosis. Differential diagnosis is presented with the ruling out of nonspecific manifestations of osteomyelitis/periostitis as the most likely alternative diagnosis.