Federici has penned a new deal to 2015.
The club's director of football Nick Hammond said: "This is a very, very important signing for us.
"Adam was the best goalkeeper in the Championship last year and I think he will prove to be one of the best in the Premier League as well.
"He is a magnificent example to young players of what can be achieved when hard work and dedication are allied with talent. We are all delighted that he has signed."
Manager Brian McDermott said: "I am really pleased to have secured Adam for another three years.
"I have known him for a number of years now, it seems like time has flown and he has constantly been developing into a top class goalkeeper.
"He is a lesson to young professionals about what is required to get to the top of your game.
"His workrate, diligence and desire are second to none and we're delighted he's chosen to commit to us again."