The Loch Lomond Youth Hostel closed its doors at the end of the last tourist season, and there are no plans to reopen in 2013.
The 14th century manor house is a 110 room facility which was used during World War Two by the anti-aircraft division.
Keith Legge, CEO of the Scottish Youth Hostel Assocation, said: "While it is always a difficult decision to close a Youth Hostel, SYHA has to make responsible decisions which support our charitable aims; we must target our resources in a sustainable way. This decision was made last year as part of SYHA's annual review process. As a not-for-profit, self-funding charitable organisation, we have a duty to make best use of scarce resources to ensure a sustainable Youth Hostel network in the future."
The building has the highest heritage rating possible, and is believed to have been sold to a private developer.