The core elements of the Green Belt of Fennoscandia are protected areas of various ranks. Such cores in the Republic of Karelia are the operating national parks Paanajarvi, Kalevalsky, Ladoga Skerries, strict nature reserve Kostomukshsky. The article describes the soil cover in the protected areas of Karelia situated within the Green Belt of Fennoscandia. Reference soils have been identified for areas of similar natural conditions, their spatial shares have been determined. A distinguishing feature of soils in the north-taiga subzone of the Fennoscandian Green Belt is the prevalence of the podzol formation process, as opposed to soils of the Karelian Ladoga coast, where podburs and brown earths are widespread. Distinctive morphological and physical-chemical properties have been noted for the podzolic soils in the northern and middle taiga of the Green Belt of Fennoscandia. The classification positions of the reference soils of the Fennoscandian Green Belt were determined according to the regional, national and international soil classifications. The resultant data can be used for soil monitoring in natural and disturbed ecosystems, and serve as a basis for protected area planning and designation in Karelia.