Breaking down into tears, Oprah says, "Our viewers have enriched my life beyond all measure. You all have graciously invited me into your living rooms, into your kitchens and into your lives. And for some of you longtime Oprah viewers you have literally grown up with me, we've grown together.
"These years with you, my viewers, have been a blessing... I want you all to know that my relationship with you is one that I hold very dear... and has brought me the greatest joy I have ever known."
"Why walk away?" she continues. "Here is the real reason -- I love this show, this show has been my life. And I love it enough to know when it's time to say goodbye."
She calls now "the exact right time" to leave.
"The countdown to the end of 'The Oprah Winfrey Show' starts now, and until that day in 2011, when it ends, I intend to soak up every meaningful, joyful moment with you."
Oprah is launching a television network, OWN: The Oprah Winfrey Network, in partnership with Discovery Communications.