Seven-time world MotoGP champion Valentino Rossi on Sunday signed a two-year deal to race with Ducati, the team announced.
Yamaha rider Rossi will replace Australia’s former world champion Casey Stoner, who will race for Honda next season after four years with the Italian team.
Rossi said he was looking ahead to a new challenge after seven years with the Japanese manufacturers.
“The time has come for me to find new challenges; my work with Yamaha is now finished,” he said.
“Sadly, even the most beautiful love stories come to an end, but they leave marvellous memories.”
Rossi, 31, finished fifth in Sunday’s Czech Grand Prix, but his chances of retaining his world title had already been compromised when he missed six weeks of the season after breaking his leg at Mugello.
“We are delighted to announce that Valentino Rossi will be with us from 2011,” said Ducati president Gabriele Del Torchio.
“He is a paragon of excellence in the world of motorcycling.”
Lin Jarvis, managing director of Yamaha Motor Racing, said Rossi had played a crucial role in the team’s fortunes.
“Valentino joined Yamaha in 2004 at a moment when Yamaha was struggling in road racing after eleven seasons without a championship victory,” said Jarvis.
“Valentino’s victory at his first GP race for Yamaha in South Africa in 2004 was an incredible moment and was just the first of many more race wins that have thrilled MotoGP fans and Yamaha fans around the world.
“His unsurpassed skills as a racer and a development rider enabled him to win four MotoGP world titles to date with us and helped Yamaha develop the YZR-M1 into the ‘the bike of reference’ for the MotoGP class.
“Whilst we regret Vale’s decision to move on, at the same time we fully respect his decision to search for a new challenge and we wish him the very best for 2011 and beyond.”