We proposed a new simple approach for estimating the oceanic rate of increase of anthropogenic CO2 (Uanth) in a subpolar marginal sea that produces ventilated water with the sea ice formation. This approach was based only on the differences in dissolved inorganic carbon (DIC) and apparent oxygen utilization (AOU) between the ventilated water and the source water. Applying our approach to the Sea of Okhotsk for 1993, 1999 and 2000, we estimated the averaged Uanth transported into the intermediate water (UI), and in the surface water from spring to fall (USs~f) and in the surface water in winter (USw) to be 1.1 ¿ 0.9 ¿mol kg-1 yr-1, 0.70 ¿ 0.01 ¿mol kg-1 yr-1 and 1.1 ¿ 0.9 ¿mol kg-1 yr-1, respectively, during the past 8 years. The accumulation rate of anthropogenic carbon was estimated as 0.78 ¿ 1012 g C yr-1 over the entire Sea of Okhotsk.