This study provides a comprehensive assessment of the mass balance of the Antarctic Ice Sheet from 1979 to 2017 using updated drainage inventories, ice thickness, and ice velocity data. The total mass loss increased from 40 ± 9 Gt/y in 1979–1990 to 252 ± 26 Gt/y in 2009–2017, with a significant acceleration in the last two decades. The mass loss was dominated by the Amundsen/Bellingshausen Sea sectors in West Antarctica, Wilkes Land in East Antarctica, and the western Peninsula. The contribution to sea-level rise (SLR) averaged 3.6 ± 0.5 mm per decade, with a cumulative 14.0 ± 2.0 mm since 1979. The mass loss is primarily driven by enhanced glacier flow in areas closest to warm, salty, subsurface circumpolar deep water (CDW), which is consistent with the strengthening of polar westerlies pushing more CDW toward Antarctica. The study highlights the significant role of East Antarctica in the mass loss, challenging the traditional view that it is stable and immune to change.This study provides a comprehensive assessment of the mass balance of the Antarctic Ice Sheet from 1979 to 2017 using updated drainage inventories, ice thickness, and ice velocity data. The total mass loss increased from 40 ± 9 Gt/y in 1979–1990 to 252 ± 26 Gt/y in 2009–2017, with a significant acceleration in the last two decades. The mass loss was dominated by the Amundsen/Bellingshausen Sea sectors in West Antarctica, Wilkes Land in East Antarctica, and the western Peninsula. The contribution to sea-level rise (SLR) averaged 3.6 ± 0.5 mm per decade, with a cumulative 14.0 ± 2.0 mm since 1979. The mass loss is primarily driven by enhanced glacier flow in areas closest to warm, salty, subsurface circumpolar deep water (CDW), which is consistent with the strengthening of polar westerlies pushing more CDW toward Antarctica. The study highlights the significant role of East Antarctica in the mass loss, challenging the traditional view that it is stable and immune to change.