The 74-year-old Rather has complained of being virtually forgotten at CBS Corp. since his exit as anchor last year, six months after a discredited story on President Bush's military service.
Rather was both gracious and blunt in a statement about his departure.
"I appreciate the words and gestures contained in today's press release by CBS," the statement began.
"I leave CBS News with tremendous memories. But I leave now most of all with the desire to once again do regular, meaningful reporting. My departure before the term of my contract represents CBS's final acknowledgement, after a protracted struggle, that they had not lived up to their obligation to allow me to do substantive work there. As for their offers of a future with only an office but no assignments, it just isn't in me to sit around doing nothing. So I will do the work I love elsewhere, and I look forward to sharing details about that soon."