Mons Claudianus lies in a remote part of the Eastern Desert of Egypt, some 500 km south of Cairo and 120 km east of the Nile, at an altitude of c.700 m in the heart of the Red Sea Mountains. The site itself is a quarry settlement known for its granodiorite, which was used for imperial building in Rome during Roman rule in Egypt. It consists of a fort and its annexes (hydreuma, stables, baths, Sarapeion). The archaeological remains show that the most intense occupation of the site occurred during the late first and second centuries AD. Between 1987 and 1993, the Institut Français d’Archéologie Orientale in Cairo conducted work by permission of the Egyptian Antiquities Organisation. The work resulted in the discovery of 9200 ostraka from the period of Roman rule in Egypt. Jean Bingen, Adam Bülow-Jacobsen, E.H. Walter, E.A. Cockle, and Van Rengen published some of these ostraka in a book entitled Mons Claudianus, Ostraca graeca et latina I (O. Claud. 1 à 190), Institut Français d’Archéo logie Orientale, Le Caire, 1992. The current study aims at casting a closer look at thirty-five of these pub- lished ostraka which form a hitherto unknown genre within the category of military documents. These thirty-five ostraka, as the publisher concludes, are passes allowing people to use the desert roads leading to the quarries, all of them dated to the reign of Emperor Trajan (98–117 AD). After reading the contents of these passes, some questions arose. Who is the issuer of the laissez-passer? Who is the addressee? What is the formula used in the communication between the issuer and the addressee? Who is allowed to pass? What information do the laissez-passers contain about the travelers and the journey along the Claudianus quarries roads? Why are people forbidden to travel along the quarries roads without a laissez-passer? What is the purpose and significance of this ban? Until now, all that has been determined is that a laissez-passer is a letter from the administration machinery of Mons Claudianus issued to all foreigners, who are not to approach the personal property of the Roman emperor, that is, Mons Claudianus, without a laissez-passer.