The aim of this article is to present the 1418 Gradual of the Poor Clares of Gniezno. The manuscript consists of 302 parchment pages. It belonged to the monastery of the Poor Clares of Gniezno from the year of its foundation (1418) until 1838, when the monastery was taken over by the Prussian government. This collection will undoubtedly shed new light on the state of musical culture in Gniezno in the Middle Ages.