The CBS network, a division of Viacom Inc., said Rather will continue to work full-time as a correspondent for both editions of 60 Minutes and other assignments for CBS News.
"I have been lucky and blessed over these years to have what is, to me, the best job in the world and to have it at CBS News. Along the way, I've had the honor of working with some of the most talented, dedicated professionals in the world," Rather said in a statement Tuesday.
Rather, 73, has come under fire for his role in a 60 Minutes Wednesday report from September that questioned President Bush's National Guard service, citing documents that later appeared to be forgeries.
He made no mention of the National Guard scandal in announcing his decision, but said he had agreed with CBS executives last summer that after the Nov. 2 election would be the best time for him to step aside as anchor and managing editor of CBS Evening News.
"I have always said that I'd know when the time was right to step away from the anchor chair. ... I have always been and remain a 'hard news' investigative reporter at heart," Rather said. "I now look forward to pouring my heart into that kind of reporting full time."
The network did not name a potential successor for Rather, who has been at CBS for more than four decades and succeeded Cronkite as the evening news anchor in 1981.
"Dan's 24 years at the CBS Evening News is the longest run of any evening news anchor in history and is a singular achievement in broadcast journalism," CBS Chairman Leslie Moonves said in a statement. "He has been an eyewitness to the most important events for more than 40 years and played a crucial role in keeping the American public informed about those events and their larger significance. ... We congratulate him on all he has accomplished and look forward to the future."
Meanwhile, an independent panel, created by CBS News to investigate what went wrong with the 60 Minutes National Guard story, continues its review and is expected to release its findings shortly.
Rather, who initially defended the National Guard story when it was first criticized, acknowledged the errors and apologized on national television.
"We made a mistake in judgment, and for that I am sorry. It was an error that was made, however, in good faith and in the spirit of trying to carry on a CBS News tradition of investigative reporting without fear or favoritism," Rather said in a statement released in late September.
One of Rather's first stories for CBS was his coverage from Dallas of President Kennedy's assassination.
The native Texan has become well known for his unusual expressions and metaphors during Election Night coverage. "Bush is sweeping through the South like a big wheel through a cotton field," Rather said on Election Day 2004.
In November 2000, Rather raised eyebrows and evoked chuckles by saying: "The race is as hot and tight as a too small bathing suit on a too long ride back from the beach."
"This knock-down drag-out battle drags on into the night. And turn the lights down; the party just got wilder. ... This thing is so wild, wacky and wooly, nobody knows how it's going to come out," the anchorman said during his marathon news coverage of the 2000 election.