The article presents a detailed analysis of the construction and content of the chronicle of the Franciscan-Reformed monastery in Chełm. The Franciscan-Reformed monastic community, although not the most numerous among the mendi-cants, played an important role in the religious and cultural life of the old Poland, which is evidenced by an extremely valuable collection of the preserved archival records. A substantial part of them is now included in the resources of the Archives of the Province of Our Lady of the Angels of the Order of Friars Minor based in Krakow. Most numerous are the archives of the monasteries of the old Reformed provinces, among which a prominent place is occupied by monastic chronicles. The 18th-century chronicle of the Chełm monastery is an interesting example of such a type of historical source. The chronicle was constructed following the then new guidelines, and it additionally has a rich iconographic layer. The analysis of the chronicle of the Chełm monastery offers a more detailed insight into the content and the scheme of the Refor-mation monastic chronicles of the 17th and 18th centuries, while familiarising the researches on the history of this period with these unquestionably valuable sources.