The Hittite rituals attributed to practitioners from Arzawa in western Anatolia have in common certain themes and elements that indicate a shared geographic patrimony in the west. Their western provenance as well as their mode of transmission to the scribal establishment in Hattusa have, however, been the subject of recent debate. Moreover, the inventory of texts assigned to this group has continued to fluctuate. Following a review the state of the discussion, in which the Arzawa corpus is defined, this article argues that the rituals from Arzawa were transmitted to Hattusa at two distinct historical junctures: the antiwitchcraft rituals in the reign of Tudhaliya I and the plague rituals in the reign of Mur- sili II. The impact of each of these influxes of new ritual material on religious production in Hattusa is examined. The resulting observations inform the attendant issue of the influence of western religious traditions on that of the Hittite empire.