The Salasacas are one of several indigenous peoples in highland Ecuador who consider themselves, and are considered by others, to be a distinct, homogeneous blood group. Throughout the Incaic, Spanish, and national periods, we trace their ethnogenesis from diverse origins to a single, highly unified ethnic community. Using an interdisciplinary methodology that combines historical and ethnographic data and follows the movement of current Salasaca anthroponyms, we identify three seventeenth-century migrations of different groups to Salasaca. These groups were still separate in the eighteenth century, and we follow their fusion into a single, exclusive, and vocal ethnic group in the postindependence period. We focus careful attention on their often novel responses to multiple historical contingencies over the course of five hundred years. Departing from writers who emphasize the political nature of ethnicity, we argue that Salasaca became a zone of cultural refusal as indigenous actors made a conscious decision to maintain a specific indigenous cultural identity.