Through John Linder, a fellow Republican congressman from Georgia, Mr Gingrich has acknowledged that he gave wrong information to the House Ethics Committee, which for months has been investigating the allegedly improper use of tax-exempt money for a highly partisan college course taught by the Speaker until 1994.
The row has already prompted the resignation of Mr Gingrich's ethics lawyer, who prepared the errant testimony, but insists his client read and approved it.
The development spells nothing but trouble for Mr Gingrich, whose waning popularity was one reason for the decline in the Republicans' majority in the House to only 20 in the new Congress which assembles next month, with the election of a Speaker one of its first tasks.
The odds remain, albeit narrowly, that Mr Gingrich will be re-confirmed as the first Republican to hold the post in 40 years, and the first to serve a second consecutive term since 1928. But even among his supporters unease is growing.
It is still not clear whether the much-delayed final report from the bipartisan Ethics Committee will be ready before 7 January, the day the Speaker is elected. But even before the latest disclosure at least a dozen nervous Republicans had indicated they wanted to see the report's conclusions before casting their votes. Throughout the controversy Mr Gingrich has insisted he has done nothing wrong, blaming his troubles on a Democratic witchhunt.
The one consolation for the Gingrich camp is the equal discomfort visited on the White House by a batch of Justice Department subpoenas issued to Clinton aides and the Democratic National Committee, seeking documents relating to dubious fund-raising by both the party and by the legal defence fund, set up to raise money to cover the President's Whitewater costs.