Mauro Icardi’s previous deal was due to expire in three years’ time but Inter have been eager to prolong the captain’s stay at San Siro.
The 23-year-old Agentina international joined Inter from Sampdoria in 2013 and has scored 58 goals in 114 appearances in all competitions.
A club statement read: “FC Internazionale is delighted to announce that an agreement has been reached to extend Mauro Icardi’s contract until June 30, 2021.
“The Argentine striker, born in Rosario, joined Inter from Sampdoria in the 2013/14 season. Since then he has scored 58 goals in 114 appearances, giving him one of the highest goals-per-game ratios in Nerazzurri history.
“And there’s a whole lot more still to come…”
Icardi has been heavily linked with a move away from Inter in recent months.
Napoli were reportedly interested in taking him south to replace Juventus-bound Gonzalo Higuain, while the player’s wife and agent Wanda Nara also claimed she had met with Atletico Madrid over a potential transfer in July.