"This is an announcement that I couldn't be happier to be making," NBC Universal President Jeff Zucker said. "Meredith's vast experience as an award-winning journalist, as well as talk show host, make her the ideal candidate for this job.
"She joins a distinguished legacy of 'Today' show co-anchors, from Barbara Walters to Jane Pauley to Katie Couric. We're lucky to have her as the newest member of 'Today,' and I am thrilled to welcome her to the NBC family."
CBS announced Wednesday that Couric would anchor "CBS Evening News," contribute to "60 Minutes" and anchor prime-time specials.
Vieira, currently seen on ABC's "The View" as well as the syndicated "Who Wants to be a Millionaire?" is to join "Today" in September.