The American singer and guitarist suffered a stroke last May and a heart attack three months later.
The stroke left him with impaired speech and he was rehabilitating at his home in Florida when he passed away.
Diddley, real name Otha Ellas Bates, created a shuffle beat on his guitar in the mid-1950s which became the basis for many R&B and rock songs.
He had a star on Hollywood's Walk of Fame, was inducted into the Rock and Roll Hall of Fame and was presented with a lifetime achievement gong at the 1999 Grammy Awards.
His best-known hits include 'Bo Diddley', 'I'm a Man', 'Say Man' and 'Who Do You Love?'
Diddley influenced musicians including Buddy Holly, John Lennon, Bruce Springsteen, Elvis Costello and The Who, as well as guitarists Keith Richards, Eric Clapton, Jeff Beck and Jimmy Page.