The new four-and-a-half year extension will keep the former Porto player at Old Trafford until the summer of 2015.
Anderson told United’s official website: “This is the best club to be at and I would like to thank everyone for the great support I have received over the years.
“I am looking forward to winning many more trophies with this club and I am so pleased to have signed a new contract.”
United boss Sir Alex Ferguson said: “We are delighted Anderson has signed a new contract.
“Anderson has developed tremendously since joining the club and he has fantastic potential at only 22 years of age, he is going to be a really top player.”
