The Queen's finances were at a "historic low" with just £1 million ($2 million) left in reserve, MPs said yesterday.
Her courtiers were advised to take money-saving tips from the Treasury.
A report by the Public Accounts Committee found the Queen's advisers were failing to control her finances while royal palaces were "crumbling".
MPs said her advisers had overspent to such an extent that her reserve fund had fallen from £35 million in 2001 to just £1 million.
The royal household had made efficiency savings of just 5 per cent over the past five years compared with government departments, that are cutting their budgets by up to a third.
MPs on the committee said the Treasury must "get a grip" and help to protect the royal palaces from "further damage and deterioration".
Margaret Hodge, the Labour chairman of the committee, said: "We believe the Treasury has a duty to be actively involved in reviewing the household's financial planning and management and it has failed to do so."
Buckingham Palace and Windsor Castle are reported to be in urgent need of repair.
Staff must catch rain in buckets to protect art and antiquities, while the Queen's old boilers were contributing to bills of £774,000 a year.
Hodge said: "The household must get a much firmer grip on how it plans to address its maintenance backlog." In April 2012 the Sovereign Grant replaced the old way of funding the royal family through the Civil List and various government grants.
The Sovereign Grant represents 15 per cent of the net surplus income of the Crown Estate, land holdings that generate money for the Treasury.
A Buckingham Palace spokesman said the sovereign grant had made the Queen's funding "more transparent and scrutinised" and was resulting in a "more efficient use of public funds".
He said that repairing the royal palaces was a "significant financial priority", and that the royal household had almost doubled its income to £11.6 million since 2007.
A Treasury spokesman said: "The new arrangements established by the Sovereign Grant Act have made the royal finances more transparent than ever while providing the long term stability necessary for good planning."