The Jāmāspi is one of the most popular Zoroastrian texts. It was probably conceived as a kind of encyclopedia for laymen. At the beginning of the last century, it was still well-known among the Zoroastrian community of India and has reached us through various manuscript traditions: Pahlavi, Pāzand and Pārsi. A philological analysis of all the manuscript traditions suggests that there was a Pahlavi archetype of the text. Moreover, it shows clearly that the Pārsi codex M52, which represents the best preserved tradition, was the result of a collation of all the existing Pahlavi and Pāzand materials. The study of the language and the narrative pattern allows us to consider the Pārsi transcription as a mechanical transcription from a Pāzand model.