The closure is expected to be the first in a series of cuts at the group as it reassesses its online activity.
The news coincides with a report in Financial Times Deutschland, which says that access to Bertelsmann's Asian websites could be restricted to members of book clubs only.
The decision will scupper plans Bertelsmann had to float the book retailing division at a time when market trends have seen online stocks nose-dive.
BOL has launched in 16 markets since it went live in 1999, giving it a bigger reach than rival Amazon. However, Amazon had already been trading online for four years by the time BOL launched, giving it an apparently unassailable first-mover advantage.
Bertelsmann's US online bookshop Barnes&Noble.com, which is a joint venture with bookstore Barnes & Noble, is not affected by the restructuring.
The news of restructuring at the German group's online operations follows similar cutbacks at rivals News Corporation, NBC and AOL Time Warner.
The General Electric-owned NBC axed 600 jobs from its online operations ahead of the slowdown in advertising and a hike in programming costs. News Corp integrated its websites with their corresponding TV networks while AOL Time Warner slashed news network CNN's workforce by 400, or 10%, in the wake of its merger earlier this year.