The new deal will keep the 24-year-old at Napoli until the summer of 2016.
Napoli president Aurelio De Laurentiis told Sky Italia: “He has just signed a renewal until 2016, I believe there won’t be uncontrollable urges to go away (on his part).
“He’s a level-handed person, he’s part of our family. When he was 20, it seemed he was 30, he has always had a good head on his shoulders.”
Hamsik has been linked with the likes of Chelsea, Manchester City, Liverpool and Paris St Germain in recent months.
