The turnover at television's top-rated morning show was anticipated. Vieira replaced Katie Couric five years ago, and has talked about wanting more free time. Vieira, 57, has three children and her husband, author Richard M. Cohen, wrote a best-selling book about coping with multiple sclerosis and colon cancer.
"Even as I say this and I know that it's the right thing, I'm really sad," she said, fighting back emotion as she made the announcement on the air Monday.
Her co-host, Matt Lauer, said that Vieira "has brought class and dignity and talent and a joy of life to this show for the last five years."
Transitions are unusual for "Today," as Vieira was still the newbie among the show's core four that included Lauer, Curry and Al Roker.
Curry has been with the show since 1997 as the news anchor. Passed over for the top job five years ago when Vieira was chosen, she stuck with the show and carved out a new reputation as a globe-trotting reporter. She was in Pakistan last week following the killing of Osama bin Laden.
"I feel like the high school computer nerd who has just been asked to the prom by the quarterback of the football team," Curry said.
Natalie Morales, an anchor for the third of the show's four hours, will become the regular newsreader. "Today" also announced that Savannah Guthrie will become a host of the show's third hour with Morales and Roker.
"Today" is careful to cultivate the image of family, and made the announcement with the five regulars seated on a couch, tossing off jokes to blunt emotion.
Vieira says she'll leave the show in June.