It was reported on Monday that the vastly experienced former England centre-back would not be offered a new deal at Old Trafford, with his contract having expired at the end of the season.
And Ferdinand, who joined United for a then club-record fee of around £30million back in 2002, has confirmed his long spell at United is over.
The 35-year-old told his official website 5mag: "I have thought long and hard over the last few months about my future, and after 12 fantastic years playing, for what I regard, as the best club in the world, I have decided the time is right for me to move on,
"I joined Manchester United in the hope of winning trophies, and never in my wildest dreams could I have imagined how successful we would be during my time here.
"There have been so many highlights, playing alongside some great players who have become good friends, winning my first Premier League title and also that fantastic night in Moscow are memories that I will cherish forever.
"Circumstances didn't allow for me to say goodbye the way I would have liked but I'd like to take this opportunity to thank my team-mates, staff, the club & the fans for an unbelievable 12 yrs that I’ll never forget. Winning trophies I dreamed about as a kid came true at this great club.
"I am feeling fit and healthy, ready for a new challenge and looking forward to whatever the future holds for me."
The former West Ham and Leeds United defender won six Premier League titles, the UEFA Champions League and two League Cups in his illustrious career with United, as well as the FIFA Club World Cup in 2008.
Ferdinand fell out of favour under David Moyes this season before the Scotsman was sacked, with his departure following that of fellow centre-back Nemanja Vidic, who opted to join Inter.
