Measurements of the δ13C of dissolved inorganic carbon primarily during World Ocean Circulation Experiment and the Ocean Atmosphere Carbon Exchange Study cruises in the 1990s are used to determine ocean-wide changes in the δ13C that have occurred due to uptake of anthropogenic CO2. This new ocean-wide δ13C data set (~25,000 measurements) substantially improves the usefulness of δ13C as a tracer of the anthropogenic CO2 perturbation. The global mean δ13C change in the surface ocean is estimated at -0.16 ¿ 0.02? per decade between the 1970s and 1990s with the greatest changes observed in the subtropics and the smallest changes in the polar and southern oceans. The global mean air-sea δ13C disequilibrium in 1995 is estimated at 0.60 ¿ 0.10? with basin-wide disequilibrium values of 0.73, 0.63, and 0.23? for the Pacific, Atlantic, and Indian oceans, respectively. The global mean depth-integrated anthropogenic change in δ13C between the 1970s and 1990s was estimated at -65 ¿ 33? m per decade. These new estimates of air-sea δ13C disequilibrium and depth-integrated δ13C changes yield an oceanic CO2 uptake rate of 1.5 ¿ 0.6 Gt C yr-1 between 1970 and 1990 based on the atmospheric CO2 and 13CO2 budget approaches of Quay et al. <1992> and Tans et al. <1993> and the dynamic method of Heimann and Maier-Reimer <1996>. Box-diffusion model simulations of the oceanic uptake of anthropogenic CO2 and its δ13C perturbation indicate that a CO2 uptake rate of 1.9 ¿ 0.4 Gt C yr-1 (1970--1990) explains both the observed surface ocean and depth-integrated δ13C changes. Constraining a box diffusion ocean model to match both the observed δ13C and bomb 14C changes yields an oceanic CO2 uptake rate of 1.7 ¿ 0.2 Gt C yr-1 (1970--1990). The oceanic CO2 uptake rates derived from anthropogenic changes in ocean δ13C are similar to rates determined by atmospheric CO2 and O2 budgets <Battle et al., 2000>, atmospheric δ13C and CO2 measurements <Ciais et al., 1995>, and GCM simulations <Orr et al., 2001>.