France international Kante, 27, signed from Leicester in the summer of 2016, has been ever-present in Maurizio Sarri's side this season.
"N'Golo Kante has today extended his stay at Stamford Bridge by signing a new five-year contract," Chelsea said on their official website on Friday.
Kante added: "I'm happy to extend my time with Chelsea, it has been two beautiful years and I wish for more to come.
"Since I came, I completely improved as a player, challenged myself and got some awards I never thought about."
Kante, whose new deal will keep him at Chelsea until 2023, signed a five-year contract when he joined the club in July 2016 from Leicester for a fee reported to be around £30million.
He arrived in England the previous summer when signed from Caen for £6m by Leicester, who he helped win the Premier League title in his first season. He was also named PFA and FWA player of the year.
Kante finished the 2016-17 campaign as a Premier League champion again with Chelsea and played a key role for France in Russia last summer when they won the World Cup.
Chelsea director Marina Granovskaia said: "We are delighted N'Golo has signed a new contract and sees his long-term future with Chelsea.
"When he arrived, we knew we had signed a special player but he has astounded everybody with his tireless and unselfish displays.
"Off the pitch, he remains a dedicated professional and a humble human being despite the fact he is a world champion and a two-time Premier League winner.
"We now look forward to five more years with N'Golo at the heart of the Chelsea midfield."
Kante made a total of 48 appearances in all competitions for Chelsea last season, scoring one goal, and has featured in 20 games in the current campaign.
