Daryl Murphy’s 22nd goal of the season gave the Blues the lead in the ninth minute but the scores are level at half-time with Jonathan Douglas having equalised for Brentford on 25.
Town boss Mick McCarthy recalled keeper Dean Gerken in place of Bartosz Bialkowski, one of four changes to the team which lost at Leeds.
While the back four was unchanges, Richard Chaplow came in on the right of midfield with Jay Tabb in the centre with Cole Skuse and Jonny Parr on the left. Murphy and Freddie Sears returned up front.
Brentford struck the first shot of the game in the third minute, one-time Town target Alan Judge cutting in from the left before hitting a low effort wide of Gerken’s right post.
As at Griffin Park on Boxing Day, Town scored with their first chance of the match, although on this occasion after nine minutes rather than 18 seconds.
Chaplow sent over a deep cross from the right, Christophe Berra nodded downwards towards goal, and Murphy added the final touch off the post at close range to claim his 22nd goal of the season and end his four-game mini-goal drought.
Four minutes after the Blues had taken the lead Sears was sent through the middle, battling with Liam Moore but was unable to shake the defender off and eventually his shot hit a defender.
The Blues kept up the pressure and on 13 Murphy almost made the most of Bees keeper David Button rushing out of his goal to the left chasing Tommy Smith’s long ball, but the Irishman hit his shot into the side-netting from a very tight angle.
On 15 Chaplow played Parr into a promising position on the left of the area but the Norwegian smashed his low shot across the face of goal.
Gerken, playing his first game since suffering a groin problem in the warm-up at Blackpool in November, was first called into action in the 23rd minute when he dived away to his left to claim Alex Pritchard’s 25-yard strike.
But two minutes later the visitors were on terms. Space was cleverly worked for Judge to cross from the right, Gerken superbly saved Stuart Dallas’s low far-post volley but Bees skipper Jonathan Douglas reacted quickly to nod home the rebound.
Brentford weren’t far from a second in the 31st minute when Judge got ahead of Parr to flick a Pritchard left-wing cross wide at the far post.
Two minutes later, the Bees failed to deal with a Tabb freekick in from the left but the ball just wouldn’t fall for Sears and then Mings. On 37 Pritchard picked up the game’s first yellow card for a foul on Skuse.
The Bees had been on top since equalising but the Blues created an opportunity in the 38th minute, Sears crossing from the right to Murphy, who was just unable to work the ball into a position from which he could shoot.
There was controversy in the 41st minute when Murphy played in Parr from the right, sending the Norwegian through towards goal on the edge of the box where he was awkwardly felled by Moses Odubajo.
Referee Scott Duncan looked to have a big decision to make but instead pulled play back to penalise Murphy - perhaps for handball - much the surprise and annoyance of the home crowd.
The Bees went close to going in front soon, Andre Gray turning Pritchard’s cross from the right only just wide after Judge had seized on a weak Mings header.
Just before the break, Tabb broke quickly following a poorly worked Brentford corner, finding Sears on the right. The ex-Colchester man crossed low to Chaplow, whose shot was saved by Button and Tabb and Murphy were unable to get onto the rebound.
The 1-1 scoreline at the break was a reasonable reflection of a game which had swung one way and then the other with both teams having had chances to add to their goal.
The Blues might have had it sealed had they taken their opportunities straight after Murphy had put them in the lead, but the Bees came back into it and deserved their equaliser when it came and had chances to get themselves in front before the break.
Town: Gerken, Chambers (c), Mings, Berra, Smith, Skuse, Chaplow, Parr, Tabb, Murphy, Sears. Subs: Bialkowski, Clarke, Anderson, Bishop, Connolly, Varney, Wood.
Brentford: Button, Bidwell, Douglas, Odubajo, Dallas, Judge, Gray, Diagouraga, Pritchard, Tarkowski, Moore.Subs: Bonham, Dean, McCormack, Toral, Jota, Smith, Long. Referee: Scott Duncan (Northumberland).