The Nigerian moves to the Baggies after spending nine seasons at Goodison Park after Steve Clarke missed out on Chelsea striker Romelu Lukaku, who takes his place at Everton
In a complicated set of events, the Toffees clinched the loan signing of Romelu Lukaku, who at one stage looked to be heading to the Hawthorns. However, after the Chelsea striker opted to move to Goodison Park on loan, Steve Clarke stepped in to sign the Nigeria international.
The Baggies also broke their transfer record earlier in the day, snapping up Stephane Sessegnon from Sunderland, adding to an attack that has yet to score in the Premier League this season.
Clarke acquired free agent Lee Camp and wrapped up a deal for Morgan Amalfitano on a season-long loan earlier on Monday.
Anichebe was in his ninth year at Goodison Park and scored 26 goals in 168 appearances for the club.