This presentation explores the possibility of using documents from the Cairo Geniza as sources for the social and economic history of Egypt during the Ottoman period (1517-1882 C.E.). The Geniza is a collection of documents that accumulated in Cairo’s Ben Ezra synagogue between roughly 1025 and 1896, when they were removed to various libraries in Europe and North America. Papers bearing the name of God were discarded in a special storage room inside the synagogue; they included everything from unique manuscripts of books of the Hebrew Bible to court cases, business letters, shipping lists, and rolls of impoverished people seeking charity. While much of the literary material, such as religious texts, is composed in Hebrew, the documentary material tends to be in Judeo-Arabic, that is, Arabic written in Hebrew letters. Most Geniza research to date focuses on the copious documents from the 11th through the early 13th centuries, when the Ben Ezra synagogue was a vibrant community center frequented by the likes of the great Jewish philosopher Maimonides (1138-1204). The much smaller Ottoman-era corpus has received scant attention. Yet these documents – in Hebrew and Ladino, as well as Judeo-Arabic and a tiny number of Ottoman Turkish texts – can shed valuable light on the socio-economic changes that Ottoman rule brought to Egypt. The information that these materials yield pertains not only to Egypt’s Jewish population but also to the majority Muslim population and the sizable Christian populations with whom the Jews routinely interacted. The presentation focuses on two Arabic documents from the Mediterranean port of Damietta. One, an inheritance case from 1538, reveals a multi-generation business partnership between a Jewish family that converted to Islam and another that retained its Judaism. The other, a business letter from 1708, centers on a Jewish convert to Islam who became one of Egypt’s grandees and was appointed Damietta’s customs director as part of a fiscal reform by the Ottoman governor of Egypt. Together, these two documents offer remarkable insights into the way converts from Judaism to Islam were perceived and received by Egypt’s Jewish community, on commercial priorities that bound the Jewish and Muslim communities, and on Ottoman efforts to revive Damietta as a commercial hub. They serve as examples of the way that Ottoman-era Geniza documents can serve as supplements to better-known archival and narrative sources on Ottoman Egypt.