The Montesinho Natural Park, NE Portugal, is a protected area of 75000 hectares, well-known for its natural values. In addition, it provides important ecosystem services, as the contribution to carbon sequestration. The paper aims at contributing to better understand the role of soils in carbon storage and its stability in the Montesinho Natural Park. The Soil Map of NE Portugal was the main information source used in the study specifically that regarding carbon and nitrogen of 14 soil profiles, representing the soil units identified as dominant in Montesinho Natural Park area. Carbon content in 0-30 cm depth was taken as indicator of carbon storage and the corresponding C/N ratio an indicator of its stability. Leptosols and Cambisols are the most represented soil units, occupying 76 and 20% of the Montesinho Natural Park area, respectively. Luvisols and Alisols together represent 2.5% of total area. Cambisols are the ones that store more carbon per unit area (7.2 kg m-2), followed by Leptosols (5.5 kg m-2), Alisols recording the lowest values (2.2 kg m-2). The carbon storage is higher in the higher altitude areas, cold and wet, soils having expressively higher carbon storage where the average annual temperature drops from 12 to 10 ºC and rainfall exceeds 1000 mm. In general, carbon stability in soils follows a similar pattern to carbon storage.
