The attacking midfielder has received the necessary paperwork to take to the pitch for boss Steve Clarke and could make his debut on Saturday against former club Sunderland
The Benin international signed a three-year contract with the Baggies on deadline day for a club record £5.5 million from Sunderland, yet missed out on Saturday's 1-1 draw with Fulham while awaiting clearance.
But the 29-year-old will be in the squad for this weekend's encounter with his former club.
"Stephane Sessegnon has been granted a work permit," a West Brom statement read.
"The Baggies' club-record signing is now available to make his debut against his old club Sunderland on Saturday."
West Brom sit one place above Saturday's opponents Sunderland in 19th place, four games into the new Premier League season.