The clubs have battled for League Two titles, League One promotions and simply for local bragging rights.
There have been memorable play-off games (for Posh at least) and high drama with both teams recording victories after being reduced to nine men.
Players and managers who have gone on to better things have been involved in the matches
The teams have met 27 times in all competitions with Posh leading the head-to-head 12-10 with five draws.
Here is a selection of dramatic highlights from Posh v MK.
9.
September 2013: Posh 2, MK Dons 1. Posh were back in League One when the rivals next met and they suffered a seventh minute red card when Nat Knight-Percival was dismissed by referee Darren Drsydale after pushing ace thespian Patrick Bamford (pictured). Five minutes later Lee Tomlin shot Posh ahead from the penalty spot and then Britt Assombalonga fired the 10-men 2-0 up before the break. Izale McLeod pulled a goal back for Dons 15 minutes from time and two minutes before Mark Little was dismissed, but the nine men hung on for victory. Photo: Midlands
10.
September 2013. MK Dons striker Patrick Bamford chases Craig Alcock during that 2-1 Posh win.
11.
September 2013. Posh defender Mark Little was shown a straight red card after a wild lunge at Dean Lewington leaving his side to see out the final 15 minutes of a 2-1 win with nine men. Photo: Midlands
12.
March 2014: MK Dons 0, Posh 2. Posh were still hunting promotion from League One when the sides clashed again at stadium:mk and two second-half goals from prolific striker Britt Assombalonga (pictured) clinched the points. Posh went onto finish sixth before losing to Orient in the play-off semi-final. MK Dons finished 10th. Photo: Midlands