Mr Trent Lott has resigned as the Republican leader in the US Senate following comments that stirred a major race controversy.
Mr Lott, who has been under intense pressure for more than a week, said in a statement he would step down from January 6th, the day before Congress resumes.
The Republicans won back control of the Senate during mid-term elections in November and Lott would have been the Majority leader, backing President George W Bush during the crucial period ahead of presidential elections in 2004.
Mr Lott, 61, had been fighting for his political life after saying his home state of Mississippi was "proud" of backing the 1948 presidential bid by Senator Strom Thurmond focusing on the segregation of blacks and whites.
In the statement, Mr Lott said: "In the interest of pursuing the best possible agenda for the future of our country, I will not seek to remain as majority leader of the United States senate for the 108th congress effective on January 6th, 2003.
"To all those who offered friendship, support and prayers, I will be eternally grateful," Mr Lott said.
"I will continue to serve the people of Mississippi in the United States Senate.
Mr Lott launched a fierce campaign to hold onto his job making five public apologies for his comments. But he got no support from the White House, opinion polls were against him and the 51 Republican senators were to meet on January 6th to decide his fate.
Mr Bill Frist, who is close to Bush, announced Thursday night that he would be a candidate against Mr Lott in the January 6th vote and several senators said Friday that they would support him.
Mr Lott made his comments at Thurmond's 100th birthday party on December 5th. Thurmond, once a strong segregationist, is just retiring from the Senate.
At the celebration, Mr Lott said: "I want to say this about my state: When Mr Strom Thurmond ran for president (in 1948), we voted for him. We're proud of it. And if the rest of the country had followed our lead, we wouldn't have had all these problems over all these years either."
It later emerged that he had made similar comments in public on at least one other occasion in recent years.
AFP