Saha was available on a free transfer after leaving Tottenham at the end of last season.
The former Manchester United and Spurs star has passed a medical and has signed a one-year contract with the Black Cats.
“Louis is a striker whose abilities have been proven at the very highest level and he brings with him a raft of experience of top-flight football,” Sunderland boss Martin O’Neill told the club’s official website.
“I’m sure he will be a great addition to our squad in an area we recognise needs strengthening and I’m delighted we have been able to complete the deal ahead of our first game of the season.”
