The results of studying the moss flora of the mountainous part of the unique European protected area – Pechora-Ilych State Strict Nature Reserve (coordinates of the bounding box around the core part of the reserve: 61.95697°N, 57.77589°E – 63.27388°N, 59.63549°E), listed as UNESCO World Heritage under the title Virgin Komi Forests, are presented. The combined (Pechora and Ilych river catchments) mountain moss flora includes 172 species from 78 genera and 33 families, which is almost a half of the reserve’s moss species diversity (348 species). It is shown that the moss floras of mountainous areas in the Pechora and the Ilych catchments demonstrate great similarity in the quantitative and qualitative features of the taxonomic structure. New data are presented on the occurrence of four rare species of mosses, listed in the regional Red Data Books of the Komi Republic and neighboring territories – Codriophorus fascicularis (protection status 2), Anomodon longifolius, Encalypta brevicollis and Lescuraea radicosa (protection status 3), and six species (Anomodon viticulosus, Encalypta ciliata, Kiaeria glacialis, Loeskypnum badium, Paraleucobryum longifolium, Pterigynandrum filiforme) in need of biological surveillance.