The 36-year-old goalkeeper has been at San Siro since 1998, and made his first-team debut for the club in January 1999 at the age of 21.
Abbiati has not always been first choice at Milan and spent three seasons out on loan with Juventus, Torino and Atletico Madrid, but became a regular after returning from the Vicente Calderon in 2008.
He made 39 appearances in all competitions this season, which saw Milan finish a disappointing eighth in Serie A.
Milan announced Abbiati's new deal on their official Twitter account.
"Christian Abbiati has extended his contract until June 30, 2015," the 18-time Italian champions stated.
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