It was a tough afternoon for the young Foxes team, who suffered a second successive away defeat by the same scoreline, following last week's loss to Arsenal.
The hosts took just three minutes to break the deadlock at Lancashire FA County Ground, with Georgie Gent firing home, set up by Junior Nsangou. The pair combined again 17 minutes in - this time Nsangou added his name to the scoresheet.
Charlie Weston put the game out of sight midway through the first half, netting a third assisted by Ethan Walker and that's how the score stayed at the interval.
A double half-time change from Ben Petty saw impetus added to Leicester's play and one of those substitutes, Zach Booth, pulled a goal back for the visiting Foxes on 56 minutes, after good play from Amani Richards.
Ten minutes later though, Blackburn regained their three-goal cushion, with Walker finding the net to round off the scoring and leave City 19th in the 26-team PL2 table, on three points from three games.
Next up in the league is the visit of Norwich City Under-21s to LCFC Training Ground on Saturday for an 11am BST kick-off.
The details...
City: Young; Cartwright, Godsmark-Ford (Grist 73'), Wilson-Brown, Ali; Richards, Cover, Amartey, Raikhy (Booth 46'), S. Thomas (Hill 46'); Maswanhise (K. Pennant 62') .
Subs not used: French.
Goal: Booth 56'.