A powerful first-half performance by Micky Adams' Foxes saw them race into a three-goal lead from which Reading never recovered.
Paul Dickov took his season's tally to 11 League goals as he struck twice, the crucial second coming from a controversial penalty midway through the first half.
Defender Matt Heath headed a third from close range 11 minutes before half time and Andrew Hughes' second-half reply for Reading proved scant consolation.
This game was the re-run of a match abandoned at half time on New Year's Day and Reading looked like being drowned in a flood of goals second time around.
Yet the home side had started the brighter in a scrappy game, Nicky Forster and Hughes both threatening before Leicester made the breakthrough.
The lively Dickov provided it with a clever finish in the 18th minute, hooking the ball over his shoulder and beyond the stranded goalkeeper Marcus Hahnemann after Matt Elliott's header had caused panic in the Reading box.
Seven minutes later Leicester doubled their advantage in controversial circumstances.
Adrian Williams was adjudged to have fouled striker Trevor Benjamin as the pair tussled for a loose ball and the arguments that raged in the aftermath produced a booking for Williams, the first of seven yellow cards in a scrappy game.
Dickov made no mistake from the spot with a cool finish down the middle of Hahnemann's goal to leave Reading in disarray.
And things went from bad to worse for the home side in the 34th minute when Muzzy Izzet floated over a free kick for Elliott to head beyond Hahnemann and leave Heath with the simplest of far post headers.
Reading, who gave a debut to new £250,000 midfield signing Steve Sidwell, gave themselves some hope nine minutes into the second half.
Forster's shot was blocked and sat up nicely for Hughes to lash home with an excellent finish.
But the home side were unable to make further progress against a well-drilled Leicester side, who re-established a six-point promotion cushion over Sheffield United.
Reading though have now managed just one win in ten outings and remain agonisingly outside the play-off places.