There have been 83 previous meetings between the sides in all competitions, and Town have the edge with a total of 35 victories.
The last meeting at The County Ground was in League One on Tuesday 20th November where a second half strike from Clayton Donaldson was enough to secure the visitors the points.
The away encounter at Griffin Park followed on Tuesday 12th March with Simon Ferry firing the Robins into a first half lead. A penalty from Sam Saunders and another effort from Donaldson sealed the tie for the Bees.
Swindon’s last League One victory over Brentford also came in a Play-Off season. Town registered a 3-2 victory thanks to a double from Billy Paynter and a goal from loanee Danny Ward in May 2010.
Former Swindon players Toumani Diagouraga and Jonathan Douglas are both expected to be involved for Uwe Rosler's side, with Town loanee Nathan Byrne a former Brentford loan player.
Tickets for the home leg of the 2012/13 Play-Off semi-final, which will take place on Saturday 4th May, are now on sale to STFC Season Ticket holders.