This article presents the results of a survey and a first assessment of the corpus of alchemical manuscripts retrieved from the Cairo Genizah, a storage room mainly intended for sacred writings that is attached to the Ben Ezra synagogue of Old Cairo. The alchemical manuscripts are described in their codicological and palaeographic features; their content is analysed in the context of the medieval production of alchemical texts in the surrounding Islamic world. The alchemical corpus of the Genizah represents a unique and widely unstudied source for our understanding of the relationship between Jews and alchemy in the medieval Mediterranean World.