Sunderland has signed free agent
Saha wrote on Twitter that he was in talks with the north-east club before his signing, on a one-year deal, was confirmed.
The 34-year-old, who left Tottenham Hotspur at the end of last season, could make his debut in the Black Cats' trip to Arsenal to open the new Premier League season this weekend.
Black Cats boss Martin O'Neill welcomed Saha's arrival as much needed to bolster a front line he has readily conceded requires strengthening.
"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," he said.
"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."
O'Neill has been frustrated in his attempts to sign a striker with reported interest in Wolverhampton Wanderers hitman Steven Fletcher so far amounting to nothing.
Fletcher handed in a transfer request last week but, with the new season just two days away, remains a Wolves player.
O'Neill's need had become increasingly pressing with 24-year-old Fraizer Campbell his most experienced striker before the arrival of Saha.
Sunderland's forward options otherwise rest with teenager Connor Wickham and South Korean Ji-dong Won after Asamoah Gyan made his loan move to United Arab Emirates club Al-Ain permanent this northern summer.
Saha left Tottenham at the end of last season after managing three goals in 12 appearances for the north London side.
The former France international has also played at Newcastle United, Fulham, Manchester United and Everton in more than a decade in English football.
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