The 35-year-old striker becomes Rovers' third signing of the summer, closely following the additions of Danny Murphy and Leon Best from Fulham and Newcastle respectively.
The forward, who scored six goals in 20 appearances last season, moves to Ewood Park following the expiry of his one-year deal with Braga.
|11/1||Blackburn are 11/1 with Sportingbet to win the Championship next season.|
Gomes has scored 29 goals in 79 games for Portugal at international level, but failed to make Paulo Bento's squad for Euro 2012 this summer.
Rovers manager Steve Kean will hope that his latest acquisition can fill the void left by the recent departure of Yakubu Aiyegbeni, who notched 17 times in the league alone last term.
The vastly experienced striker has made 437 club appearances across spells at Boavista, Benfica, Fiorentina and Braga, scoring 167 goals along the way.