During Muslim times, Egypt was an important centre of the textile industry and Jews occupied an important place, both in the manufacture and in the commerce of textile products. In this article you will find the translation of two letters written to a Jewish manufacturer and merchant of textile products (Ebü'l-Ferec Yusuf b. Avkal) by his assistant (Mûsâ b. Hisdâ). The main subjectof the letters are the problems tied to labour and the workers and the relations between workers and businessmen, during the high season of flax, the plant from which linen is made. The letters give also clues about the literary style current in the commercial correspondence of the time.