Sammy Igoe broke Brentford hearts with a 82nd minute winner after they deserved much more. The ex-Reading midfielder condemned Brentford to their fourth concecutive defeat after putting up more than a stiff resistance to the League's fourth-placed side.
The defeat leaves Brentford in the bottom four with a vital home game to Stockport County next week - a munst win game if Brentford are to avoid the drop.
Wally Downes selected a 4-5-1 formation, dropping Andrew Frampton and Tommy Wright from Tuesday's defeat at Brighton with striker Ben May ploughing a lone furrow up front.
Andy Gurney tested Bees goalkeeper Stuart Nelson in the eleventh minute with a thirty-five yard shot that fizzed past his right-hand post.
Two minutes later, Swindon opened the scoring. Brian Howard's free-kick - awarded for a foul on Gurney by Ronnie Bull - found Andy Gurney via the head of Tommy Mooney. Gurney had the simple task of adding the final touch from six yards with Brentford's defending leaving a lot to be desired.
Brentford levelled things on the half-hour mark. Kevin O'Connor
broke up a Town attack to feed Ben May, who confidently fired home a left-footed shot from ten yards.
The Bees frustrated their hosts after the break, but Swindon forced several corners, Brentford defending in numbers. Andy King introduced Rory Fallon with sixteen minutes remaining and his first touch almost lead to Swindon's second. He was denied by Stuart Nelson, who dived superbly to his right to push the ball away.
But Swindon were to claim all the honours in the 82nd minute. Tommy Mooney's long ball was headed away by Ronnie Bull but Sammy Igoe volleyed the ball past the unsighted Nelson from the edge of the penalty area.