FIGC president Maurizio Beretta has approved the proposal for 12 substitutes to be named for Serie A matches.
The change comes only three months after the idea was initially presented to the organisation by Napoli president Aurelio De Laurentiis.
Serie A teams will be forced to name no fewer than 23 players on a match day, making their benches the largest in the highest tiers of world football.
The ruling that only three of the 12 substitutes can take to the field remains unchanged.
The decision will also be valid for Coppa Italia, Supercoppa Italiana and Primavera Championship fixtures effective immediately.
However, the move has already been met with stiff opposition from Roma coach Zdenek Zeman, who believes an 18-man match day squad to be sufficient.
“For me it does not change very much,” he told reporters.
“It’s unnecessary. In my experience 18 players was sufficient.”
The Serie A season kicks off on Saturday, with the opening fixture involving Fiorentina and Udinese set to be the first game to experience the changes.