The East Antarctic Ice Sheet (EAIS) is currently surrounded by relatively cool water, but climatic shifts have the potential to increase basal melting via intrusions of warm modified Circumpolar Deep Water (mCDW) onto the continental shelf. Here we use an ice sheet model to show that under the current ocean regime, with only limited intrusions of mCDW, the EAIS will likely gain mass over the next 200 years due to the increased precipitation from a warming atmosphere outweighing increased ice discharge due to ice-shelf melting. However, if the ocean regime were to become dominated by greater mCDW intrusions, the EAIS would begin to lose mass after 200 years, with George V Land being particularly affected. We also find that a moderate warming scenario is likely to result in a more negative mass balance than an extreme warming scenario, as the relative difference between increased precipitation and ice discharge is greater in the moderate warming case.