Samur-Yalama National Park in Azerbaijan is a region of biodiversity characterized by forests rich in various species of flora, including bryophytes. This article studies the diversity of leafy mosses common in the study area. More than 100 collected herbarium materials along different route lines were identified using hand magnifiers, Motic Digital Microscope and identification key. Of the collected species, Bryum algovicum Sendtn. ex Müll. Hal. were identified as new species for Azerbaijan. In addition, the species Bryum pallens Sw., Brachythecium mildeanum (Schimp.) Schimp., Plagiothecium laetum Schimp. and Taxiphyllum wissgrillii (Garov.) Wijk et Marg. were identified for the first time for Samur-Davachi lowland botanical-geographic region. In addition, it was determined that 70 species were included IUCN Red List as Least Threatened (LC) category. Three species - Palamocladium euchloron (Bruch ex Muell. Hal.) was included as Endangered (EN), Dicranum muehlenbeckii Bruch & Schimp as Vulnerable (VU) and Leucodon pendulus Lindb. as Not Evaluated (NE) category.