The 35-year-old has lost his place in the United team over the last two years due to a series of injuries and it had been widely expected the former England defender would be allowed to quit Old Trafford at the end of this season.
Ferdinand’s contract expires in July and he has revealed he will not be signing an extension after regularly being left out as Phil Jones, Jonny Evans and Chris Smalling have been preferred to him this term.
In a statement on his website, Ferdinand said: “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.”
Ferdinand made his last appearance for United on Sunday when he played in their 1-1 draw at Southampton on the final day of the Premier League campaign.
His departure brings an end to a glorious 12-year stay at United, during which time he won six league titles, two League Cups, one Champions League and a Club World Cup.
Ferdinand made 454 appearances, scoring eight goals, following his then British record £30 million ($50 million, 36 million euros) transfer from Leeds in 2002.
The ex-England captain has no desire to retire and is now looking for a new club.
“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,” Ferdinand added.
“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 (beating Chelsea to win the Champions League) 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 and the fans for an unbelievable 12 years 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.”
Ferdinand, who won 81 caps for England before retiring from the international stage, signed a one-year extension to his United contract last year, but he found first-team opportunities harder to come by this season, making just 14 Premier League appearances.
The decision to let Ferdinand go ignores the advice of interim manager Ryan Giggs, who insisted earlier this month the centre-back could still make a useful contribution and should be offered a new deal.
United confirmed Ferdinand’s announcement in a posting on their official Twitter account: “MUFC would like to thank Rio Ferdinand for his long and distinguished service, and wish him well for the future.”