Life with United has not always been smooth for Fletcher, who joined the club in 2000, but the 27-year-old has become a significant figure in Sir Alex Ferguson's squad in more recent years.
So much so in fact, that his absence through suspension was cited as one of the reasons why United performed so badly in the 2009 Champions League final against Barcelona.
Ferguson said: "Darren has been at the club since he was 15.
"I am extremely proud that he came through the ranks of our youth academy and am delighted Darren has signed a new contract.
"He has developed into a top-class midfielder."
Fletcher has now made 288 appearances for United, scoring 21 goals. He has won three Premier League titles, the FA Cup, two League Cups, the Champions League and the FIFA Club World Cup.
In addition, he is the current Scotland skipper, having inherited the armband from Barry Ferguson.
Although a Celtic fan born in Dalkeith, Fletcher moved south in his teens and was prevented from making his debut as a schoolboy due to FA regulations.
He has never made any secret of his passion for the Red Devils and is one of the players Ferguson will look to carry on the United traditions once Ryan Giggs and Paul Scholes have accompanied Gary Neville into retirement.
"I take great pride in playing for Manchester United," said Fletcher.
"I have won many trophies in my years playing here and I am looking forward to winning many more in the seasons to come.
"I would like to thank everyone at the club."
