The 23-year-old was initially a huge success in Italy after signing as a teenager in 2007 but has struggled with injury over the last season-and-a-half, scoring just one Serie A goal in limited action.
The former Internacional striker has decided to return to his homeland ahead of the 2014 World Cup in Brazil.
"Corinthinas have acquired 100 per cent of the rights to Alexandre Pato. The player will arrive in the coming day for a medical and sign a four-year contract," Corinthians confirmed.
Pato scored 63 goals for the Rossoneri, but did not find the net in Serie A this season.