Attorney Brent Bryson tells The Associated Press that King died peacefully in his sleep at 9:40 p.m. PDT Thursday at his home in Las Vegas.
The one-time farmhand brought new fans to the blues and influenced a generation of musicians with his heartfelt vocals and soaring guitar on songs such as "The Thrill Is Gone."
PHOTOS: B.B. King's career over the years
King sold millions of records worldwide and was inducted into the Blues Foundation Hall of Fame and the Rock and Roll Hall of Fame.
King played a Gibson guitar that he affectionately called Lucille and was not only the undisputed king of the blues but a mentor to scores of guitarists including Eric Clapton.
He was awarded his 15th Grammy in 2009 in the traditional blues album category for "One Kind Favor."