We travel to the National Hockey Stadium in Milton Keynes for a third round clash against Martin Allen's men, kick-off 7.45pm.
Last season's defeat to Grimsby Town at the second round of the competition still hurts and skipper Ledley is determined to progress this time around.
"The cups are our chance to win silverware and get into the UEFA Cup, so every game is important," said Ledley. "Grimsby was a great disappointment, we let ourselves down on the night and we'll do all we can to make sure there is no repeat of that this season.
"Defeats like that do linger and they are the defeats you remember because you lose games in the Premiership and recover quickly but when you lose to a lower league side in the cup it stays with you.
"You look forward to ease the memory at the next opportunity and this is that chance.
"It's another tough one and that's always the case with an away game like this. It's their cup final and if you don't do it right, you'll get beat. They will have the work ethic, the determination and quality and we have to match that."
Meanwhile, Ledley was happy to reflect on Sunday's Premiership victory over West Ham, a 1-0 success with Mido on target in first half stoppage time.
"After such a good performance in the UEFA Cup in Turkey there was always a possibility with all the travelling that we might be a little tired but this was a massive game, West Ham at home and we were looking forward to it.
"The tired legs soon went out of the window - we were up for the game and even though we might not have been at our best, the team spirit was great and with that, the determination to get the three points.
"If you look at the chances, they had one in the first half and not too much else. Although we didn't keep the ball as well as we can, in spells we put moves together, quick breaks and created the better chances.
"We could have won it two or three-nil but in the end we had to dig deep and see out a 1-0 victory."
Ledley King has stressed that we need to match the work ethic of MK Dons to progress in the Carling Cup tonight.