The city of Nishapur occupied a major position on the Silk Road in eastern Iran. Although excavations were carried out in the 1930s, its history during Late Antiquity and the Middle Ages still remained obscure. The Irano-French archeological mission at Nishapur from 2004 to 2007 (CNRS - MAEE - Musée du Louvre) concentrated on the Qohandez, or citadel, which is the most ancient area of the site. Its stratigraphy and ceramics are presented in this publication.