Lott, 66, scheduled two news conferences in his home state later in the day to discuss his plans. According to congressional and White House officials, who spoke on condition of anonymity ahead of the announcement, Lott intends to resign effective the end of the year.
No reason for Lott's resignation plans was given, but according to a congressional official, there is nothing amiss with Lott's health. The senator has "other opportunities" he plans to pursue, the official said, without elaborating. Lott was re-elected to a fourth Senate term in 2006.
Lott's colleagues elected him as the Senate's Republican whip last year, a redemption for the Mississippian after his ouster five years ago as the party's Senate leader over remarks he made at retiring Sen. Strom Thurmond's 100th birthday party in 2002. Lott had saluted the South Carolina senator with comments later interpreted as support for southern segregationist policies.
After the 2006 elections, when Democrats recaptured the Senate, Lott was put in charge of lining up and counting votes as whip, the No. 2 job behind minority leader Mitch McConnell.
Lott becomes the sixth Senate Republican this year to announce retirement. Democrats hold a 51-49 majority in the chamber.
Mississippi's Gov. Haley Barbour, a Republican, will appoint Lott's replacement, who will serve until the 2008 elections, when voters will elect someone to serve out the balance of Lott's term, which runs through 2012. Rep. Chip Pickering of Mississippi, a former Lott aide who recently announced his retirement from the House, is widely seen as a potential successor. Aides to Pickering said he would withhold comment until after Lott's news conference.
The smooth-spoken Lott found himself in hot water in December 2002 after going too far in his praise of Republican Sen. Strom Thurmond at the South Carolinian's 100th birthday party. Lott said Mississippi voters were proud to have supported Thurmond when he ran for president on a segregationist platform in 1948, and added: "If the rest of the country had followed our lead, we wouldn't have had all these problems over all these years either."
A few days later, Lott issued a statement saying he had made "a poor choice of words" that "conveyed to some the impression that I embraced the discarded policies of the past. Nothing could be further from the truth, and I apologize to anyone who was offended by my statement."
But the damage was done. President George W. Bush distanced himself from Lott's remarks, telling an audience the comments "do not reflect the spirit of our country."
Lott then made a round of public appearances, apologizing for his gaffe. He called his remarks "insensitive" and said he regretted "reopening old wounds and hurting so many Americans." He also apologized on Black Entertainment Television and promised to use his position to help push through initiatives that would benefit minorities.
Lott later wrote in a book - "Herding Cats: A Life in Politics" - that President Bush hurt his feelings by disavowing the comments in a tone that was "devastating ... booming and nasty."
Another event during Lott's exile changed his relationship with the White House: Hurricane Katrina. The massive storm devastated Lott's home state, not to mention his oceanside home in Pascagoula. He found his refrigerator a few blocks away in a neighbor's yard. For him, the administration's bungled response was personal. He considered retiring.
Before his Senate job, Lott served in the House, where he worked closely with other young conservatives, including Georgia's Newt Gingrich, and showed his party loyalty by defending President Nixon at 1974 impeachment hearings. In 1981 he became the Republican whip, responsible for vote counting and making sure members toe the party line. He served in that post until 1988 when he easily won the Senate seat vacated after 41 years by Democrat John Stennis.