Gil Cates, who will produce the March 5 televised Oscar ceremony, said Stewart was "the epitome of a perfect host--smart, engaging, irreverent and funny."
Academy President Sid Ganis said Stewart, who follows the likes of comedians Chris Rock, Billy Crystal and Steve Martin, was "a terrific addition to our roster of great hosts."
Stewart's Daily Show, which airs on the Comedy Central network, has won multiple Emmy awards and become one of the United States' most popular cable TV shows in the past six years.
"As a performer, I'm truly honored to be hosting the show," Stewart said. "Although, as an avid watcher of the Oscars, I can't help but be a little disappointed with the choice. It appears to be another sad attempt to smoke out Billy Crystal."
Producers of the telecast have made strenuous efforts in recent years to lure back younger viewers to Hollywood's biggest night. Rock, last year's host, introduced an edgy, provocative tone to the show and drew a mixed reception.
The 78th Academy Awards will be presented in Hollywood on March 5 in a live television broadcast by ABC.
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