The anthropogenic CO2 accumulation rate for the North Atlantic Ocean was estimated on the basis of the decrease in the δ 13C of the dissolved inorganic carbon measured between cruises in 1981 (Transient Tracers in the North Atlantic), 1993 (OACES) and 2003 (Repeat Hydrography). A mean depth-integrated δ 13C change of -15.0 1 3.8? m yr-1 was estimated by applying a multiple linear regression approach to determine the anthropogenic δ 13C decrease at 22 stations where δ 13C depth profiles were compared. The largest and deepest anthropogenic δ 13C decreases occurred in the subpolar ocean and, in contrast, the smallest and shallowest decreases occurred in the tropical ocean. A mean anthropogenic CO2 accumulation rate of 0.63 1 0.16 mol C m-2 yr-1 (0.32 1 0.08 Pg C yr-1) in the North Atlantic Ocean over the last 20 years was determined from the mean depth-integrated δ 13C change and a ratio of anthropogenic δ 13C to DIC change of -0.024? (5mol kg-1)-1. Only half of the accumulated anthropogenic CO2 in the North Atlantic during the last 20 years was the result of air-sea CO2 uptake, based on a comparison of the air-sea 13CO2 flux to the DIC13 inventory change, with the other half likely a result of northward advective transport.