North Karelian Biosphere Reserve and adjacent areas of Finland were studied in 1996 2001 for bryophytes in 21 fragmented old-growth spruce forest stands. In total 194 bryophyte species (119 mosses and 75 liverworts) were recorded, including nine of Red List of Finland (Anastrophyllum hellerianum, Calypogeia suecica, Cephalozia macounii, Harpanthus scutatus, Herzogiella turfacea, Lophozia ascendens, Polytrichastrum pallidisetum, Riccardia multifida, R. palmata). The bryophyte flora is analysed with respect to species composition and distribution within the area, ecological groups and frequency of species. The groups of mosses and liverworts common for the North Karelian Biosphere Reserve and adjacent areas and conservation issues are considered. The main characteristics of the floras of studied spruce stands are connected with the amount of rotting wood, shaded rocky outcrops and presence of constant moisture and admixture of deciduous trees. Distinctive features of the flora are defined in comparison with the Central Norway spruce stands.