An understanding of the main controls on carbon accumulation in naturally saline peatlands can be useful for furthering peatland reclamation in the Athabasca Oil Sands Region where salinization complicates construction of sustainable peatland ecosystems. As such, the long-term apparent rate of carbon accumulation (LARCA) within a naturally saline fen situated near Fort McMurray, Alberta was studied using two peat cores. Changes in LARCA in less saline part of the fen coincide with water table fluctuations and seem not to be affected by low salinity (soil EC <5 mS cm⁻¹). The highest LARCA values were associated with wet conditions; however, prolonged inundations coupled with high salinity (soil EC >10 mS cm⁻¹) appear to have had a negative effect on LARCA. In the more saline part, salinity seem to have a notable effect on LARCA – hydrology links. Mean LARCA of the site (19.7 g⁻² yr.⁻¹) is lower than in western continental fens. The northern less saline part of the fen (soil EC <5 mS cm⁻¹) has LARCA of 29.67 g⁻² yr.⁻¹ that is close to LARCA in continental fens, but LARCA in the southern part (soil EC >10 mS cm⁻¹) is considerably lower (9.79 g⁻² yr.⁻¹).