The 29-year-old, who moved to Stamford Bridge from Liverpool in August 2011, made 48 first-team appearances for the European champions, scoring six goals.
Following reports earlier today claiming that Meireles had signed a three-year contract with the Turkish outfit, Chelsea have now officially confirmed that the player has left the club.
"Raul Meireles has today joined Fenerbahce on a permanent transfer," read a statement on the club's official website.
"The move was completed before the close of the Turkish transfer window later this week.
"Chelsea Football Club thanks Raul for the part he played in such a historic and successful year, and wishes him well at his new club."