As sixteenth-century Spaniards constructed their global empire, they carried with them the racial-religious concept of “limpieza de sangre,” or blood purity, which restricted marginalized communities from exercising prestige and authority. However, the complex demographic arena of early modern America, so different from the late medieval Iberia that gave rise to the discourse, necessarily destabilized and complicated limpieza's meanings and modes of expression. This article explores a variety of ways by which indigenous elites in late colonial Mexico sought to take advantage of these ambiguities and describe themselves as “pure-blooded,” thereby reframing their local authority in terms recognized and respected by Spanish authorities. Specifically, savvy native lords naturalized the concept by portraying their own ancestors as the originators of “pure” bloodlines in America. In doing so, they reoriented the imagined metrics of purity so as to distinguish themselves from native commoners, mestizos, and the descendants of Africans. However, applying limpieza in native communities could backfire: after two centuries of extensive race mixing, many native lords found themselves vulnerable to accusations of uncleanliness and ancestral shame. Yet successful or not, indigenous participation in the discourse of limpieza helped influence what it meant in New Spain to be “honorable” and “pure,” and therefore eligible for social mobility.