Mike Fondop's 84th-minute header rescued a point for Oldham to maintain their play-off push while denting MK Dons' League Two title hopes.
Marvin Ekpiteta's 30th-minute strike was the first time Oldham had conceded the opening goal since Valentine's Day.
On that occasion they drew 1-1 with Fleetwood and it was the same outcome again as Fondop scored his eighth goal of the season, and third in four games, to keep Latics in the hunt for the top seven.
It looked like it would not be their day after Aaron Collins' left-wing cross was met by Ekpiteta at the far post and he headed past goalkeeper Mathew Hudson.
MK Dons were hopeful of their first win in four games to put pressure on leaders Bromley.
But they did not do enough to test Hudson again and Fondop took advantage, rising to meet substitute Josh Hawkes' cross and glance a header past Craig MacGillivray.
The MK Dons keeper's fingertips denied Fondop a stoppage-time winner, while Curtis Nelson headed over for the visitors in the closing stages.
Match report supplied by PA Media.
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