We compare alkalinity and total dissolved inorganic carbon (DIC) measurements made during the Transient Tracers in the Ocean, North Atlantic Study (TTO-NAS) in 1981 with modern measurements from a TTO reoccupation cruise in 2004 (M60/5). We find that the TTO-NAS alkalinity values are 3.6 ¿ 2.3 ¿mol kg-1 higher than modern alkalinity data tied to Certified Reference Materials. The TTO-NAS DIC values re-calculated from original alkalinity and discrete-pCO2 data using currently accepted constants are 3.8 ¿mol kg-1 higher than those reported in the revised TTO data set. This difference is reduced to 0.7 ¿mol kg-1 when our suggested correction to the TTO-NAS alkalinity is applied. These re-calculated DIC values are 2.4 ¿mol kg-1 too low relative to contemporaneous measurements made by the vacuum extraction/manometric Certified method. Application of this correction brings the TTO data into almost perfect agreement with modern measurements for slowly-ventilated deep water of the eastern Atlantic.