The new four-year contract will keep Cech at Stamford Bridge until the summer of 2016.
The 30-year-old has been a key player for Chelsea since joining the club from Rennes in a £7million deal in 2004.
“I am really happy to be part of this great club for another four years,” said Cech.
“I hope the next four years will be as successful as the last eight years I have been at the club.”
Blues chief executive Ron Gourlay added: “Chelsea fully appreciates the highly significant contribution Petr has made to the most successful period in the club’s history.
“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.”
