The 40-year-old defender has played in 851 official matches for Inter since moving to the Nerazzurri outfit from Argentinian club Banfield in 1995.
"I feel the time has come," Zanetti told La Nacion. "I feel fulfilled and complete.
"To retire at almost 41 still feeling in form has no price.
"Football has given me so much and I've enjoyed every moment."
Zanetti ruptured his Achilles tendon last year but came back and has featured in 10 league games for Inter this season.
"After last year's injury, I really wanted to prove that I could still compete and I've managed to do so," he said.
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