Town made it a perfect start to the new year with goals from David Wright and Jason De Vos extending the unbeaten home run to 17 games.
Pablo Counago and Kevin Phillips both hit the woodwork in the first-half before Wright got the breakthrough midway through the second period with a brilliant nearpost header from Liam Trotter's cross.
De Vos wrapped up the points six minutes from time with his second goal of the season to take Blues back into the Play-Off positions.
Town made four changes from the team that lost at Coventry, Alex Bruce and Sito coming back from injury to replace Fabian Wilnis and Chris Casement. Trotter and Gavin Williams starting in place of the suspended Tommy Miller, with Alan Lee dropping to the bench.
Former Town skipper Tony Mowbray was given a warm reception from the home fans on his return to Portman Road, the Albion boss seeing his side top of the Championship before kick-off.
Albion controlled possession over the first 10 minutes but it was Blues that caused the first threat, Counago denied by Dean Kiely's speed off his line to clear.
Phillips then forced Neil Alexander into a save from Zoltan Gera's cross, then Jon Walters wasted the best chance of the first-half when he blazed over the bar after bursting clear.
Paul Robinson then used his experience and no little strength to shoulder Walters out inside the box, while Jason De Vos and Bruce combined to clear from Ishmael Miller and the Manchester City loanee looked to get in on goal.
Walters was denied by Robinson again as Town matched the Championship leaders blow for blow, Trotter failing to take advantage of the rebound.
Counago's influence on the game was growing by the minute and a short pass into the box was hammered goalwards by Danny Haynes, Kiely beating the ball out.
Miller wasted an excellent chance for Albion at the far post, heading wide after Jonathan Greening's sublime pass had released Gera for a cross.
Williams picked up his fourth booking of the season for a foul on Phillips. Counago then had the Town faithful on their feet just past the half hour mark with a 18 yard strike that cannoned back of the inside of the post.
Phillips then followed suit from further out, his long range strike hitting the top of the bar.
Gera's shot was blocked by Wright's brave challenge with Williams blasting wide at the other end to bring an entertaining first-half to a close.
The second-half began as the first-half finished, Phillips losing control of the ball inside the Town box, Counago going down under a challenge from Bostjan Cesar in the penalty area but no spot-kick, while Phillips shot over from eight yards.
Williams' quick free-kick fed Counago and the Spaniard slipped in Haynes whose cross was cleared behind by Cesar at full stretch.
Counago joined Williams in referee Trevor Kettle's notebook for dissent, Alexander then saving well from Phillips' 20 yard strike.
The Baggies made the first change of the game with Roman Bednar and Craig Beattie forming a new strikeforce with Miller and Phillips making way on 65 minutes.
Walters ambitious effort went well wide, Kiely then dealing with Sito's cross as Town looked the more likely to break the deadlock, the Albion 'keeper then denying Trotter after the midfielder got on the end of Walters' knockdown before Blues got the deserved goal, Wright involved initially in the move, then heading in Trotter's cross at the near post.
Town could have wrapped the game up a minute later, Sito setting up his countryman but Counago couldn't beat Kiely from eight yards, the full-back then hitting Kiely with the rebound.
Albion made a final change with Filipe Teixeira replacing Morrison with 13 minutes left on the clock. Lee then coming on for Trotter. Hoefkens booked for a foul on Williams.
From another foul then extended the lead on 84 minutes, Counago brought down by Gera and De Vos heading in at the far post from Williams' delivery.
Cesar was booked for a foul on Counago, the Town striker then replaced by Billy Clarke for the last three minutes as Blues eased to a deserved win and a place back in the top six.
Town: Alexander, Sito, De Vos, Bruce, Wright, Haynes, Garvan, Williams, Trotter (Lee 81), Walters, Counago (Clarke 87). Subs not used: Supple, Legwinski, Wilnis. Booked: Williams, Counago.
West Brom: Kiely, Hoefkens, Cesar, Pele, Robinson, Gera, Greening, Koren, Morrison (Teixeira 77), Miller (Bednar 65), Phillips (Beattie 65). Subs not used: Albrechtsen, Brunt. Booked: Hoefkens, Cesar.
Att: 24,000



















