This study presents basin-wide anthropogenic CO2 inventory estimates for the Indian Ocean based on measurements from the World Ocean Circulation Experiment/Joint Global Ocean Flux Study global survey. These estimates employed slightly modified &Dgr;C* and time series techniques originally proposed by Gruber et al. [1996] and Wallace [1995], respectively. Together, the two methods yield the total oceanic anthropogenic CO2 and the carbon increase over the past 2 decades. The highest concentrations and the deepest penetrations of anthropogenic carbon are associated with the Subtropical Convergence at around 30¿ to 40¿S. With both techniques, the lowest anthropogenic CO2 column inventories are observed south of 50¿S. The total anthropogenic CO2 inventory north of 35¿S was 13.6¿2PgC in 1995. The inventory increase since GEOSECS (Geochemical Ocean Sections Program) was 4.1¿1PgC for the same area. Approximately 6.7¿1PgC are stored in the Indian sector of the Southern Ocean, giving a total Indian Ocean inventory of 20.3¿3PgC for 1995. These estimates are compared to anthropogenic CO2 inventories estimated by the Princeton ocean biogeochemistry model. The model predicts an Indian Ocean sink north of 35¿S that is only 0.61--0.68 times the results presented here; while the Southern Ocean sink is nearly 2.6 times higher than the measurement-based estimate. These results clearly identify areas in the models that need further examination and provide a good baseline for future studies of the anthropogenic inventory. ¿ 1999 American Geophysical Union