The myth of an archetypal hero, either divine or human, slaying a dragon-serpent who is most often blocking access to a body of water is very ancient. Various water-related rituals and their attendant myths arose out of the vital dependence of the prehistoric Indo-European peoples on rivers to maintain their way of life. “Killing a dragon” was a symbolic way of "freeing of the waters" and also exercising control over the potentially chaotic vicissitudes of flowing water. In performing this task, the dragon-slaying hero ensured fertility and thus the continued survival of his community. In light of the mythological connection between dragons and water, this paper considers whether dragon-slaying myths can be further connected to the Iranian water goddess, Arəduuī Sūrā Anāhitā and the Avestan saošiiant.