The 25-year-old, who arrived from Norwegian club Lyn in 2006, is now under contract at Stamford Bridge until 2017.
“Chelsea seems like my home now because I have been here for over six years and I enjoy my time here,” Mikel said.
“I have basically won everything with Chelsea and those years have been really special for me, winning trophies with big names like Didier Drogba, John Terry and Frank Lampard, who have had very long Chelsea careers.
“Last season, to win the Champions League was even more special, and I hope these next five years will bring even more success and I can win trophies with the new players we have here.”
Mikel has made 261 appearances during his time at the club, scoring twice, and has won the Premier League once, the FA Cup four times, the League Cup, and the Champions League.