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.
17.
December 2017: MK Dons 1, Posh 0. One of the more embarrassing Posh defeats of recent times. MK defender Joe Walsh was sent off in the seventh minute before Chuks Aneke gave the home side the lead. Osman Sow (pictured) was then dismissed in the 35th minute to leave MK with over an hour to play with nine men and yet they rarely looked like conceding. Photo: Midlands
18.
September 2018: MK Dons 3, Posh 3. Posh were 3-0 down at half-time in this Checkatrade Trophy tie, but hit back to draw 3-3 with goals from George Cooper (pictured), Jamie Walker and Matt Godden. Posh scored twice in the last three minutes, but Steve Evans' side lost the subsequent penalty shootout. Photo: Midlands
19.
August 2019: MK Dons 0, Posh 4. A brilliant Marcus Maddison strike opened this game up for Posh who won comfortably as Mo Eisa (2) and Ivan Toney also netted. Eisa is pictured scoring his first goal with a shot that travels past current MK boss Russell Martin. Photo: Midlands