The &dgr;13C of dissolved inorganic carbon (DIC) decrease (the 13C Suess effect) in the Indian Ocean was calculated using a multiparameter linear regression comparison of the 1978 Geochemical Ocean Sections Study and 1995 World Ocean Circulation Experiment &dgr;13C of DIC, hydrographic, and nutrient data. The surface ocean &dgr;13C decrease rate along 80¿ and 115¿E ranged from approximately -0.1? decade-1 at 55¿S to a maximum of approximately -0.18? decade-1 at ~35¿S and decreased northward to around -0.13? decade-1 at the equator. Using a global extrapolation based on ocean model results [Bacastow et al., 1996] and previous &dgr;13C changes calculated from 1970 to 1993 station reoccupations in the Pacific Ocean and based on preformed &dgr;13C versus chlorofluorocarbon age trends in the Indian, Pacific, and Atlantic Oceans [Sonnerup et al., 1999], an ocean-wide average surface ocean &dgr;13C rate of change of -0.15 to -0.17? decade-1 was estimated. The average depth-integrated &dgr;13C change rate between 1978 and 1995 along 80¿ and 115¿E was -6.9¿0.5?myr-1 from 58¿S to 5¿N. ¿ 2000 American Geophysical Union