Sean McManus, president of CBS News, Tuesday announced Dan Rather is leaving the network after 44 years as an anchor and reporter.

"Of all the famous names associated with CBS News, the biggest and brightest on the marquee are Murrow, Cronkite and Rather," McManus said. "With the utmost respect, we mark the extraordinary and singular role Dan has played in writing the script of not only CBS News, but of broadcast journalism."

Rather was unable to reach an agreement with CBS on a new contract.

During his four decade-long career with CBS News, Rather wrote six books, anchored six presidential election campaigns and covered a dozen wars on five continents.

In 44 years he has braved hurricanes and floods, been beaten by a crazed maniac, dodged bullets and mouthed off to presidents, but he was discredited two years ago when he aired a questionable report on President George Bush's Air National Guard service during the Vietnam War.

Rather will be succeeded by former Today Show host Katie Couric.