The Belgian has scored 43 goals and contributed 46 assists in 147 appearances for Chelsea since joining from French side Lille for ??32m in 2012.
Hazard was named in the PFA Team of the Year in each of the last two years and lifted Chelsea???s Player of the Year accolade last season.
The 24-year-old has started every league game for this season and is the club???s second highest scorer, with 13 goals in all competitions.
“I am very happy to sign a new contract with Chelsea,” Hazard said.??”Since I came here in 2012 I have always felt good and the club has been very supportive to me.
“The manager has helped me improve a lot, the fans have been fantastic and I have an amazing understanding with my team-mates.
“I always try to give pleasure to the supporters with my style of play and it is nice to know they appreciate my work.
“I hope we can repay that support by winning lots of trophies, beginning with the Capital One Cup at Wembley, and after that, we can push hard towards the end of the season.”
Chelsea manager Jose Mourinho added: “I am very happy that Eden has signed a new contract. It shows he believes in the club???s coaching staff and players to help him become the best player in the world.
“He is already a top player and his evolution has been fantastic. He is still very young and he can become the best.”
Hazard has completed more dribbles and suffered more fouls than any other player in the Premier League this season.