The central midfielder will be a Viola player until the end of the forthcoming season having left San Siro last month following the end of his contract with the Rossoneri, for whom he had played for since 1995.
|16/1||Fiorentina are 16/1 with William Hill to win Serie A
The Serie A side's official website stated: "Fiorentina wish to communicate that the club have purchased the rights to the player Massimo Ambrosini.
"The footballer has signed a contract that will bind him to the club until 30 June 2014."
The 35-year-old is a two-time Champions League winner and joins the likes of Marcos Alonso from Bolton, Joaquin from Malaga and Marko Bakic from Torino as a new Artemio Franchi arrival this summer.