The Czech keeper, who joined the club in 2004, has already played more games for Chelsea than any overseas player - 369 appearances which has seen him win three Premier League titles, four FA Cups and two Carling Cups plus the Champions League after a penalty shoot-out.
Cech said: "I am really happy to be part of this great club for another four years. I hope the next four years will be as successful as the last eight years I have been at the club."
The 30-year-old stopper made a series of crucial saves in Chelsea's victorious FA Cup and Champions League campaigns last season.
He saved Arjen Robben's penalty in extra time in the European competition final against Bayern Munich and two more in the shoot-out.
Chelsea chief executive Ron Gourlay said: "Chelsea fully appreciates the highly significant contribution Petr has made to the most successful period in the club's history, and it is very important to our aim of continuing this level of achievement that he has committed himself to the club until 2016.
"It is clear to anyone who watched the climax to the season just completed that Petr continues to perform as well as any goalkeeper in the world."
Over the course of his Chelsea career Cech has kept 178 clean sheets, an astonishing 48% of games he has played in.
Source: PA
Source: PA