This article explores the usage of Arabic and Hebrew scripts to write Arabic in the Jewish community of medieval Egypt. Factors leading to the employment of particular alphabets include schooling, class, and professional and religious identity. Certain professions, such as doctors, preferred the Arabic alphabet as a sign of their trade and integral part of their prestige, whereas merchants needed knowledge of Arabic script for conducting business and arranging transport. Highly educated community leaders may choose to write in both alphabets as a personal quirk. Other authors prefer to compose Hebrew in Hebrew script, and Arabic only in Arabic letters. The motivation of writers to favour Arabic or Hebrew script and the complexity of their choices is discussed along the lines of examples in legal documents, letters, medical books, and grammatical and geographical works from the Cairo Genizah, the great treasure trove of medieval manuscripts.