The frontman revealed he may have done it in 1974 when a somersault went wrong while filming rock opera Tommy.
But the injury could date back even further to a Boys’ Brigade camp in 1953 when he was thrown in the air in a blanket and landed badly.
Daltrey, 74, recalled: “I was in agony.”
Scans revealed the injury in 2007 when the My Generation singer went to hospital after blacking out.
He said: “A doctor walked in with a chest X-ray and asked, ‘So, Mr Daltrey, when did you break your back?’ Politely, I pointed out that I hadn’t.
“Politely, he pointed out that I had.
He had the evidence, right there on the X-ray – one previously broken back, one not very careful owner.”
In his new book, Thanks A Lot Mr Kibblewhite: My Story, the veteran star said: “We were filming I’m Free for Tommy in 1974.
“One minute 15 seconds in, you’ll see me being thrown into a somersault by an Army bloke.
“It was an easy enough stunt but I fell badly.”