WASHINGTON - In the last week of January, five members of Congress joined the hottest demographic group on Capitol Hill: Republicans who are heading for the exits.

Reps. Tom Davis of Virginia, Kenny Hulshof of Missouri, Ron Lewis of Kentucky, Dave Weldon of Florida and James Walsh of New York are among 25 Republican members of the House of Representatives who have announced their resignations or retirements. The party is closing in quickly on its record of 27 House retirements, set in 1952.

"It's become an epidemic," said David Johnson, a Republican strategist based in Atlanta.

While some members, such as Hulshof, are leaving to pursue new political opportunities, most observers say that the mass departures are the result of the loss of Republican control in the 2006 elections, lackluster fundraising and low morale.

So far, only five House Democrats have announced that they're leaving, either to retire or to run for Senate seats.

Prospects look equally bright for Democrats in the Senate, where five Republican veterans -- John Warner of Virginia, Pete Domenici of New Mexico, Chuck Hagel of Nebraska, Larry Craig of Idaho and Wayne Allard of Colorado -- are ready to hang it up.

It adds up to a tough year for Republicans, who at a minimum will face a big loss of seniority and experience when the 111th Congress convenes next January. Analysts predict that the party will be hard-pressed to keep Democrats from expanding their 232-199 House majority.

"It means that whatever little chance there was -- and it always was a little chance -- that they could take back the House is pretty much gone. ... Open seats are always easier to win," said Robert Smith, a professor of political science at San Francisco State University.

He said that many retiring Republicans had discovered that after running the House for more than a decade, "it's not as satisfying to go to the other side."

Johnson, who worked on Republican former Kansas Sen. Bob Dole's 1996 presidential campaign and has overseen numerous congressional races, said that four more House Republicans could step aside this year. That would break the party's record.

"I would say there's a good possibility, depending on how the polls continue to look," Johnson said. "The Republican brand right now is damaged. Voters are not blaming the Democratic Congress, even though the polls show that Congress is held in such low esteem. Voters are blaming Republicans more than they're blaming the Democrats who are in power. ... All of a sudden we're playing defense."