There are two schemes of creation in Zoroastrianism. According to one, Ohrmazd fashions the world in the manner of a skilful craftsman. According to the second, Ohrmazd gestates and gives birth to the world. This article is about the latter. The relevant Pahlavi texts are presented and discussed. The article argues that Pahlavi authors used macrocosm-microcosm correspondence theory to elaborate the doctrine from Avestan rudiments.