AbstractPrevious archaeological studies suggest that terminal Middle Horizon Tumilaca populations (cal A.D. 950–1150) of the middle Moquegua Valley represent direct descendants of earlier Chen Chen-style Tiwankau colonists of the region. This study tests this idea by comparing dentally derived biodistance analyses of Tumilaca, Chen Chen-style, Tiwanaku, and other regional samples. The results indicate that the Tumilaca and Chen Chen-style mortuary samples are similar to one another suggesting that these populations might share an ancestral-descendant relationship. The phenetic relations of the Tumilaca and Chen Chen to other regional samples are also discussed.