Aaron Wilbraham put the Dons ahead in front of the 14,528 crowd, but Chris Whelpdale equalised.
The Dons then had a succession of chances in the second half, including one from Kevin Gallen that they failed to convert as the League Two title race remains evenly poised.
The first half was a tight affair and goals aside there was little action, with Posh probably just edging it on possession.
But the opener on 12 minutes came from the home side and was one of quality. Jemal Johnson burst down the left and cut the ball back for Colin Cameron who set up Wilbraham with a cute pass that the striker blasted home from eight yards.
The Dons failed to dominate from then on though and the tricky George Boyd hit the side-netting from a tight angle on the left.
It was a sign of more danger to come and Posh scored a deserved equaliser on 27 minutes.
It was sloppy play from the Dons on all accounts though as Dean Keates was given too much time to cross to Whelpdale at the back post, who had got the wrong side of Mark Wright as he headed coolly home.
Peterborough looked confident after that, without creating too much. The Dons did have a good chance on the stroke of half-time but Johnson shot miles over after Wilbraham's knock-down.
The Dons stepped up their game considerably in the second half and had a good shout for a penalty when Wilbraham went down in the box from Dean Lewington's free-kick.
In reply, substitute Scott Rendell forced a good save from Willy Gueret with a curling effort from the edge of the box.
The game had burst into life by now and substitute Kevin Gallen turned Chris Westwood superbly but squared to Wilbraham, who had the goal gaping, a second too late and the ball was cleared.
The Posh goal continued to lead a charmed life and, with just under 20 minutes left, Lloyd Dyer's curling shot was almost parried into his own goal by Lewis.
Paul Ince was then left further frustrated as Wilbraham somehow miscued wide from ten yards out after good work by Cameron.
And the Dons then should have taken three points with the last kick of the ball as great work in the box presented Gallen with an easy chance that he somehow shot wide from just six yards.
His manager and the crowd looked on in disbelief as the teams remain locked together at the top of League Two.