The former Juventus and Italy head coach, led the Blues to the league title in his first year in England, finishing seven points clear of Tottenham.
The new contract is an improvement upon the terms of the three-year deal the 47-year-old agreed when he moved to Stamford Bridge, tying him to the club until 2018/2019.
“I am very happy to have signed a new contract with Chelsea. We worked extremely hard in our first year to achieve something amazing, which I am very proud of. Now we must work even harder to stay at the top.
“The Chelsea fans have given me so much support since I arrived here one year ago and it is important we continue to succeed together,” Conte told Chelsea’s official website.
Chelsea director Marina Granovskaia said: “Antonio achieved incredible success last season, adapting to English football very quickly and leading us to the Premier League title.
“This new contract reflects our belief that he can continue to deliver results both domestically and as we return to European competition in the Champions League.”