At least twenty-two sanctuaries of Demeter and Kore in Asia Minor and the islands off the western coast are attested by archaeological evidence. More than 272 epigraphic sources, nearly all of which are translated and discussed in this study, further document the cults of both goddesses in these regions. This monograph is the first study to draw on such a substantial body of material in order to demonstrate the cultic connections between cities in the Greek East and other parts of the Greek world. The archaeological and written sources provide insight into both regional and Pan-Hellenic features of the sanctuaries of Demeter and Kore, including their architectural layouts, the iconography of votive offerings, festivals, rituals, and the development of these practices over time. In assessing these regional and Pan-Hellenic characteristics, the analysis draws on the full range of archaeological and written evidence from across the Greek world. The available evidence indicates that the cults and sanctuaries of Demeter and Kore in the Greek East largely retained Greek characteristics; however, in certain regions, such as Caria, their cults were partially shaped by indigenous religious traditions. Despite Greek and later Roman hegemony, the cult of Demeter in other parts of Asia Minor, beyond western Asia Minor, was unable to supplant the cult of Cybele and other local chthonic fertility deities.