Rep. J. Dennis Hastert, who served as House speaker longer than any other Republican, bade farewell to his colleagues today, confirming that he will not complete his 11th term.

Mr. Hastert, 65, did not say exactly when he will resign, but indicated it will be soon. He said his speech would be his last from the House floor. The 110th Congress will end in January 2009.

He later told reporters, “I think I’ll be gone by the first of the year.”

In his 16-minute address, Mr. Hastert recounted his career’s high points, concluding: “It’s time for this legislator to return to being a private citizen.”

The speech marked a rare moment of bipartisan warmth in the House. Most members attended and gave Mr. Hastert a long ovation. Speaker Pelosi, Democrat of California, introduced him by his old title, calling him “the distinguished speaker of the House.”

Mr. Hastert told his colleagues: “My heart is still here, and always will be.”

He had announced in August that he would not seek re-election in 2008, and hinted that he had little interest in staying through the end of the current Congress.

His resignation will trigger a special election in his Chicago-area district, which includes Aurora and Elgin, Ill. The winner will face re-election next November.

Democrats say they will compete for the seat, but the district clearly leans Republican.

Mr. Hastert became speaker in January 1999 after two better-known party members were forced aside by scandals and intraparty rivalries. He lost the post when Democrats regained control of the House after the 2006 elections.