Italy's goalkeeper Gianluigi Buffon (Photo: Reuters)
His previous deal had been due to expire in 2013 and Buffon said he had asked for a one-year extension but the Serie A club had offered two.
"Juventus has become a way of life for me. When something gets inside you, you can't see yourself in another shirt," Buffon, who joined from Parma in 2001, told a news conference.
The 34-year-old, who won the World Cup with Italy in 2006, said he had no plans to retire and had one eye on the European championship in 2016.
"I never put limits or deadlines on my career.
"In a year and a half there is a World Cup and in three and a half years a European (championship). I think I can get to that," said Buffon, who has 123 caps.
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