The Croatian 34-year-old has reportedly agreed a deal with the Serie A leader until the end of the current season, with the option of extending for a further year.
He will join Zlatan Ibrahimovic in attack and will wear the Number 9 jersey.
Mandžuki? has won 24 trophies including 1 Champions League, 1 UEFA Super Cup, 1 FIFA Cup World Cup, 9 championships and 12 between National Cups and Super Cups. He is the second-highest Croatian scorer ever with 33 goals in 89 appearances for the national team.