Second-half goals from Wes Thomas, Nouha Dicko and a double from Thomas Ince handed Michael Appleton his first win as Blackpool boss in a game that they dominated for large parts.
The first-half was largely a non-event but Blackpool sprung into life in the second period and deservedly took the three points.
The Seasider had the first attempt on target after five minutes when Ince's right-wing free-kick was glanced goalwards by Craig Cathcart but straight into Bobby Olejnik's hands.
Lee Tomlin looked lively and instigated most of the Peterborough's attacks early on, while Blackpool were typically threatening down the flanks.
Just before the 20-minute mark Tiago Gomes let fly from 30 yards but his drive went narrowly high and wide of Olejnik's goal.
Moments later George Boyd had a great chance to give the home side the lead when he found himself one-on-one with Gilks, but the Pool stopper won the battle and turned his effort around the post.
There were a couple of stoppages for injuries midway through the half and that disrupted both teams as the game began to get a little ragged and scrappy.
Needless fouls crept into both sets of players and there was not much rhythm to the play as the first-half drew to a close.
The half ended with sustained possession for Pool but they couldn't break through an organised Posh defence.
HALF-TIME: PETERBOROUGH 0-0 BLACKPOOL
The Seasiders started the second-half on the front foot and in the 50th minute Michael Appleton's side deservedly took the lead.
After a slong passing move it was Thomas who was on hand to nod home Ince's chipped cross.
GOAL: Peterborough 0-1 BLACKPOOL
Shortly after the goalscorer could have had a second but Olejnik made a good save down to his right from Thomas' left-footed shot.
Blackpool continued to have the majority of the ball and it was Thomas again at the heart of the action when he won his side a penalty after a weaving run in from the left.
Ince stepped up and calmly slotted home the spot-kick, sending the keeper the wrong way.
GOAL: Peterborough 0-2 BLACKPOOL
What ever the manager said at half-time worked as The Seasiders seemed like a different team at the start of the second-half, passing the ball around well and creating chances.
Just as Blackpool were looking comfortable a weak back pass from Alex Baptiste was poked home by Dwight Gayle and The Posh were back in it with 20 minutes remaining.
GOAL: PETERBOROUGH 1-2 Blackpool
A couple of minutes later Ince nearly restored the two-goal advantage but his shot from an acute angle, after rounding the keeper, found the side netting.
The home side gained some confidence from the goal and could have levelled but Shaun Brisley's volley was too close to Gilks and the keeper saved with ease.
The Seasiders then steadied the ship, bringing on Angel Martinez and Nouha Dicko and it was the two substitutes who combined to restore Blackpool's two-goal lead.
Martinez overlapped Ince before crossing low and hard for Dicko to bundle the ball in from a few yards out.
GOAL: Peterborough 1-3 BLACKPOOL
Blackpool were now comfortable again and put a bit of gloss on the scoreline when Ince broke away down the right and curled in a great left-footed effort, which even the home fans applauded.
GOAL: Peterborough 1-4 BLACKPOOL
Appleton's side saw out the game and almost got a fifth in stoppage time but Kevin Phillips' chip was saved well by Olejnik.
FULL-TIME: PETERBOROUGH 1-4 BLACKPOOL