Thurmond, R-S.C., turns 100 on Dec. 5 and is retiring after serving in the Senate for 48 years - longer than any member.
"If you know his personal story, you're almost out of breath if you understand what he has done over his lifetime," Sen. Byron Dorgan, D-N.D., said of Thurmond. "This is a man of great personal courage. I deeply admire what Sen. Strom Thurmond has given to this country. "
Thurmond is one of five long-term senators retiring this week. Among them is conservative icon Sen. Jesse Helms, who is stepping down after serving five terms.
Sen. Robert Byrd, D-W.V., called the 80-year-old Helms a "Southern gentleman of the first order."
"He has never wavered in the strength of his convictions or his vote," Byrd said of Helms, R-N.C. "We have always known where Sen. Jesse Helms stands."
The other senators retiring are Sen. Phil Gramm, R-Texas, Fred Thompson, R-Tenn. and Frank Murkowski, R-Alaska, who earlier this month was elected governor of his home state.
Several other senators are leaving after losing re-election bids.
Sens. Tim Hutchinson, R-Ark., Bob Smith, R-N.C., Max Cleland, D-Ga. and Jean Carnahan, D-Mo., lost their seats to challengers. Sen. Robert Torricelli, D-N.J., dropped his re-election bid just weeks before the election after seeing his approval ratings plummet.
Carnahan, defeated two weeks ago by former Missouri Rep. Jim Talent, took to the Senate floor to reflect on her Senate career, which began two years ago after her husband, Mel, was killed in a plane crash just before the election. After voters elected Mel Carnahan posthumously, Jean Carnahan was appointed to the job.
"Two years ago, when I came to U.S. Senate it was with a heavy heart. Life had not turned out the way it was supposed to," Carnahan said. "But life is not the way it's supposed to be. Life is the way it is. It's the way we cope with it that makes the difference."
"I leave realizing that to have served in the United States Senate for even a short while is an honor afforded very few," Carnahan said. "I still believe, as did my husband, that public service is a good and noble work, worthy of our lives."
By Janelle Carter