The official Xbox Store says Ubisoft's Assassin's Creed Syndicate will have an instalation size of 40.7GB on Xbox One.
Last year's Assassin's Creed Unity also featured a 40GB install, but some users had to download the full game twice due to a bug in that game's 6.7GB patch.
Syndicate is set in London in 1868, with some of the DLC taking place 20 years later in 1888 to allow players to tackle Jack the Ripper.
The game will not feature multiplayer or a companion app, though there are microtransactions.
Assassin's Creed Syndicate launches October 23rd on PS4 and Xbox One, with the PC version coming November 19th.
