Zanetti joined Inter Milan in 1995 and was captain for the side that won the treble last season.
“I am very happy. I didn’t expect to be here for so long with a team as important as Inter,” he told ESPN.
“I am very happy to have played all these games with the blue and black shirt. Being captain for so many years is a reason to be proud.
“I have a contract for another two years in which I hope to play. Then I will judge how I feel in that moment.
“I will certainly end my career at Inter.”