The midfielder follows hot on the heels of Petr Cech and Wayne Bridge in putting pen to paper on long-term contracts.
Essien 25, was bought for £25m from Lyon in 2005.
Chelsea are gearing themselves up for a period of stability in their ranks.
By offering these lucrative contracts, Chelsea are sending out signals to possible suitors to back off or pay almost impossible transfer fees.
Chelsea have being stung by the contract debacle surrounding Frank Lampard who is now in his last year of contract.
In January he will be free to talk to another club and in July leave Stamford Bridge for nothing.
It will be noticable to those NOT offered new deals, that they may soon be considered surplus to requirements.
Chelsea have left behind Claudio Pizarro from their China and Russia tour, suggesting that he will be out of SW6 within weeks. Tal Ben-Haim is expected to move to Manchester City while Shaun Wright-Philiips is wanted by Portsmouth.
Kharid Boulahrouz and Claude Makelele have already left.
Andriy Shevchenko has decided to stay put and hope Chelsea will not buy Samuel Eto'o. He will be delighted that Chelsea are pursuing Real Madrid's Robhino as that's just the sort of wide player who will provide him with the ball in and around the penalty area.
Didier Drogba is also still in the UK. This time the club insist it's due to an injury that needs treating.