Wimbledon striker Jason Euell scored twice for the Dons at Selhurst Park as the London outfit claimed only their second home league win of the season.
The margin of victory was closer than it should have been, after the Dons conspired to miss a glut of first-half opportunities.
Despite the absence of John Hartson from the Dons starting line up, they did not lack fire power and the combination of Euell and Wimbledon home grown talent Patrick Agyemang caused the visitors problems all afternoon.
An injury to Par Karlsson after only five minutes looked as though it would add to the tale of woe Dons boss Terry Burton has suffered this season at Selhurst Park, but his enforced exit and the addition of Marcus Gayle proved to be the catalyst for victory.
After a glaring miss from Wimbledon centre half Dean Blackwell in the first minute of the game, the Dons dominated the opening period only allowing Preston one strike at goal.
After an embarrassing miss on eight minutes by Agyemang, Wimbledon took the lead just after the quarter hour through Euell.
The Wimbledon striker, who has been subject of much transfer speculation this season, took his tally for the term to 13 goals as he capitalised on some indecision by Preston keeper David Lucas to give his side the lead.
The Dons' leading scorer could have had a hat-trick by the break but a combination of smart keeping by Lucas and poor finishing meant the home side only led by a single goal at the break.
Despite defensive reorganisation by Preston boss David Moyes at the interval, Wimbledon doubled their lead five minutes into the second period.
Trond Andersen picked out Euell in the middle of the Preston penalty area, and he beat Lucas at the second time of asking.
Preston caused the Dons moments of concern in the second half, Steve Robinson had an effort ruled out for offside, before they finally reduced the arrears in the 63rd minute.
Robinson scored a 20-yard free kick, following a foul on striker David Healy on the edge of the Wimbledon penalty area.
This pressure proved to be short lived, as with five minutes of the game remaining Dons centre half Mark Williams connected with a Neal Ardley corner to give Wimbledon only their second victory in 18 attempts at Selhurst Park.