Loris Capirossi will race for Suzuki next season with an option to stay on in 2009, the Italian Ducati rider said on Thursday.
"I am happy with the five years spent at Ducati because they were exciting seasons and we won some good races together.
"But the moment has come for a change and to try new challenges," he told Italian media ahead of this weekend's Czech MotoGP.
Capirossi, who is eighth in this season's standings, will link up with Australia's Chris Vermeulen at the Japanese team.
A source said last week Italy's tax agency had ruled that Capirossi evaded taxes in 2001-02. Former world champion Valentino Rossi is being probed over suspected tax evasion.