They went in 3-0 up at half time with ex-Preston Striker David Healy scoring a brace of goals and virtually sealing the points.
Leeds went 1-0 up after 13 minutes when a Jermaine Wright corner floated over everybody to the unmarked Brian Deane at the far post and the veteran striker's header went into the top corner of the net.
Healy made it two when his 10-yard shot went into the bottom right-hand corner of the net after Chris Lucketti failed to clear and the ball rebounded to the Northern Ireland international.
Wright had a shot saved by Gavin Ward who pushed the ball for a corner from which Clarke Carlisle had a header saved.
Man of the match Healy made it 3-0 just before half time when he beat Lucketti and Claude Davis before shooting under Ward.
Richard Cresswell scored in the 53rd minute for Preston with a right-foot shot into the bottom corner following an Eddie Lewis assist.
Preston pushed forward looking to get back in the match and Paul McKenna had a shot straight at Neil Sullivan.
Minutes later Lewis again tested the United keeper but the visitors almost settled the match when Deane brought a wonderful save from Ward with a powerful header.
Leeds did make if 4-1 after 72 minutes when John Oster's cross was headed down by Deane at the far post and Simon Walton had an easy tap in.
Preston refused to give in and pulled a consolation second goal back seven minutes from time when Dickson Etuhu's cross was steered in by Cresswell.