Andrea Dovizioso will partner Jorge Lorenzo at Ducati for the next two MotoGP seasons after signing a new contract.
Dovizioso joined the Italian team from Yahama as Valentino Rossi's replacement in 2013.
The 30-year-old, whose only win in the top class was the British MotoGP for Honda in 2009, finished seventh in the riders' standings last season, two places and 26 points behind teammate and fellow Italian Andrea Iannone.
Iannone only joined the team from Pramac last year but will make way for defending champion Lorenzo, who will arrive from Yamaha next season.
Ducati are still searching for their first titles since they won the manufacturers' crown when Casey Stoner was champion in 2007.
"I'm very pleased to have reached this agreement with Ducati and to be able to continue the adventure we began in 2013," said Dovizioso.
"Over the years we worked hard and have managed to bring a great level of competitiveness and therefore I'm convinced that soon we will get the rewards we all deserve."