Brno: 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."