The American collided with a car on the Rimini coastline in Italy while cycling last week.
He was taken into the intensive care unit of Cesena’s Maurizio Bufalini Hospital and has had his family by his side for the last five days.
But the hospital today announced he’d lost the fight for his life.
A statement read: “The medical college has confirmed the death of the patient Nicholas Patrick Hayden, recovering from Wednesday May 17 in a hospital intensive care unit of Cesena Bufalini as a result of serious multiple injuries occurred on that date.”
NICKY HAYDEN DEAD: Has the reason for horror crash been revealed?
Hayden, who had been racing for Red Bull Honda’s World Superbike team, won the MotoGP championship in 2006.
He had raced in the World Superbike Championship in Italy last Sunday.
It emerged this morning that video footage had been found taken from a resident’s state-of-the-art surveillance system which was close to the scene of the hit.
According to Italian newspaper Rimini Today, the images are of good quality and have been seen by police officers who are investigating.
Hayden was knocked off his road bike by a Peugeot 207CC last Wednesday.
There are rumours in Italy that say Hayden pulled out the junction without looking before the car hit him. It’s also being investigated whether the fact Hayden was listening to music could have been a factor.
Investigators found headphones connected to an iPod at the scene.
Hayden’s crash in Italy is being investigated by police after the deputy prosecutor in Rimini, Paolo Gengarelli, opened a file on the incident.
He has appointed police road expert Orlando Omicini to reconstruct the exact dynamics of the accident.
It is not known what speed the driver of the Peugeot was travelling at when he collided with Hayden.
The driver took a breathalyser test and was found not to have exceeded the alcohol limit.
The police reconstruction report is expected to be ready by mid-July.
The report is expected to focus on the speed of the car in the hope of establishing what happened.
The stretch of road where Hayden was knocked over has a 50km/ph speed limit.
Fans rushed on to Twitter to pay tribute to Hayden as the news broke this afternoon.
One fan wrote: “R.I.P Nicky Hayden, gone too soon. #RIPKentuckyKid.”
Another tweeted: “A TRUE RIDER. Thoughts with family and friends. @NickyHayden #NickyHayden #GoNicky.
A fellow tweeter posted: “Rest in peace, Nicky.”
While cyclist Jody Cundy, who has represented Great Britain at six Paralympics, posted: “Sad to hear the news of Nicky Hayden passing away from his injuries sustained in a cycling accident last week. #gonicky #RIP69.”
Another user said: “We will miss you @NickyHayden thank you for fight till the end ride in peace #RIPNicky.”
