The Argentine will spend next season with Massimiliano Allegri's side after a frustrating campaign with the Nerazzurri last season.
The 28-year-old joined the Nerazzurri from Palermo last season, but he failed to nail down a regular starting spot for the club. Milan, meanwhile, is in need of defensive reinforcements following the injury suffered by Daniele Bonera and subsequently wasted little time in pursuing its interest in the Argentine.
It had looked as though his move across the Milan rivals had been called off, but the Rossoneri soon revived their interest and have gotten their man for the next year, with the deal containing an option to make the move permanent next summer.
"Inter announce that the Argentine defender Matias Silvestre has been transferred to AC Milan on loan with an option to buy," an Inter Milan club statement read.
The center back began his career at Boca Juniors and first made the move to Serie A back in 2008, when he joined Catania. Silvestre spent three years at the Angelo Massimino before moving to their Sicilian rivals and earned a 6 million euro move to the San Siro a year later.