Nicolas Anelka opened his Baggies account to cancel out Joe Cole's opener, before Saido Berahino had the final say following strikes from Modibo Maiga and Kevin Nolan.
Joe Cole opened the scoring inside the first four minutes for the home side, only for Anelka to return to haunt former manager Sam Allardyce - who signed the Frenchman for Bolton Wanderers back in 2006 - with a brace that put West Brom in command.
|VIEW FROM UPTON PARK
|By Chris Davie
West Ham’s disjointed campaign at both ends continues as a makeshift center back partnership was exposed, while an attacking display was never cohesive enough to cause West Brom significant problems.
Sam Allardyce’s men got off to a bright start with the opener after just four minutes but West Brom was rewarded for its lengthy spells in possession with a double from Nicolas Anelka, his first two goals since arriving at the Hawthorns in the summer, which gave Keith Downing’s charges the lead heading into the break.
Modibo Maiga replaced a stagnant Carlton Cole at halftime and the 26-year-old provided the equalizer and the assist to hand the home team the advantage once again.
But West Brom was not to be denied and Saido Berahino, who displayed clever movement throughout the game, wriggled enough room to get a shot away which beat Jussi Jaaskelainen.
A draw keeps West Ham in the relegation zone, while West Brom leapfrogs Norwich City and Aston Villa into 13th spot.
But West Brom refused to lie down and secured a share of the spoils after 69 minutes, Saido Berahino's fine individual effort ensuring West Ham remains in the relegation zone, although the visiting team could not find a late winner and is now nine without a league triumph.
Jussi Jaaskelainen returned to West Ham's XI in place of Adrian, while Berahino and Anelka led the line for West Brom in six changes made by interim head coach Keith Downing.
The visiting side went close early on when Chris Brunt volleyed into the side-netting from James Morrison's cross.
However, the club fell behind moments later, Joe Cole slotting home with a cool finish following neat link-up play with Kevin Nolan.
James Tomkins was forced off with a groin injury, and replaced by Guy Demel, and the switch seemed to give West Brom the initiative in possession as the team dominated play.
However, it was the home side which continued to create the better opportunities, Carlton Cole heading well over from a Matt Jarvis corner before Demel shot wide from point-blank range.
Mark Noble spurned another chance for West Ham as he curled a free kick off target, and Allardyce's men were made to pay for their profligacy just five minutes before the interval when Anelka converted from Brunt's through ball to net for his sixth different Premier League club.
Anelka capitalized on poor defending from West Ham in first-half injury time to score his second after the home team had failed to clear Brunt's corner.
Maiga was brought on for Carlton Cole at the break and made an instant impact, testing the reflexes of Foster before finding the net in the 65th minute with a curling shot that crept under the England goalkeeper's body.
The turnaround looked to have been completed two minutes later when Nolan bundled the ball home for a Maiga knock down to score only his second goal of the campaign.
There was to be yet another twist in the tale, which came courtesy of England Under-21 international Berahino, who teased the West Ham defense before firing in off the post.
West Brom finished the contest the stronger of the two sides, Berahino hit the woodwork with a free kick, but the visitors could not find a dramatic late winner.