David Healy grabbed a last-minute winner as Preston ended a poor run of five defeats in their last six games.
Preston dominated the first half and, in the 21st minute, Claude Davis fired a 25-yard shot narrowly wide of the left-hand post before Ricardo Fuller hit the crossbar with a long-range curler.
In the 30th minute Healy played a one-two with Richard Cresswell before seeing his shot saved by Marcus Hahnemann while Chris Lucketti headed wide of the left-hand post.
At the other end Andy Hughes brought a save out of Andy Lonergan.
Preston made it 1-0 after 35 minutes when Davis and Fuller combined to find Healy who took the ball round Hahnemann before hitting a left-foot shot into the net.
Just before half time, Michael Keane hit the crossbar as Preston threatened to run riot.
Early in the second half, Lloyd Owusu kicked out at Tyrone Mears on the halfway line and was sent off by referee Mr Jones.
Reading were forced to bring on Dave Kitson for Scott Murray and Preston brought on Eddie Lewis for Davis.
However, the Royals pressed for an equaliser and when John Salako crossed for Hughes, his header was cleared off the line by Lucketti.
Fuller had a shot cleared off the line by Nicky Shorey before Salako equalised after Hughes' cross had been knocked down by Kitson.
However, in the last minute, Healy made it 2-1 when he fired a close-range shot low into the bottom right-hand corner of the net.