The Foxes looked well on their way to a first win at Blackburn since 1997 when Jamie Vardy tapped in, but Matthew Kilgallon's glancing header just before half-time ensured Blackburn avoided a third straight home defeat.
How the game stayed level thereafter was a mystery though, as both sides went for the jugular in a game that saw misses from close range, Vardy somehow hitting the post, and a clearance off the line.
Despite seeing their lead at the top of the Championship cut to five points, Leicester remain unbeaten in 2014, while Blackburn are now two games without defeat thanks to the spirited comeback.
Blackburn made two changes following last week's win, with the injured Jason Lowe missing out. On-loan Liam Feeney made his full debut.
There were no such problems for Nigel Pearson, who named an unchanged XI after the win over Blackpool and his team were quickly in their stride.
David Nugent and Vardy had scored 32 Championship goals between them before the game and that tally was soon added to.
Nugent's curling effort from 20 yards in the 20th minute was heading into the top corner but Paul Robinson made a stunning save.
However it did not matter as the Foxes kept the ball alive and Ritchie De Laet crossed for Vardy to tap in his 16th of the season goal.
Last week's hat-trick hero Jordan Rhodes thought he had replied instantly but his 12-yard effort was thwarted by Kasper Schmeichel's instinctive save.
Leicester's dominance continued and Riyad Mahrez's first touch on the left saw him breeze past Adam Henley but Vardy scooped his cross over the bar.
Almost out of nowhere though, Blackburn were level. De Laet's back-pass under no pressure was wild and went out for a corner, and from the set-piece Kilgallon's near-post header found its way in despite Anthony Knockaert's best efforts.
The Championship's leading scorers should have been back in front after 53 minutes when a long ball evaded everybody and Vardy rounded Robinson, but unbelievably he struck a post and the rebound just evaded Nugent.
Rovers then created two great chances of their own. Craig Conway jinked past two players before fizzing in a cross that Michael Keane put over, and soon after that opening Conway was denied by a sprawling Schmeichel save.
The league leaders were rattled and Kilgallon almost headed in for the second time after meeting Rudy Gestede's flick-on but only found the side-netting.
Tommy Spurr was Blackburn's hero after 72 minutes when he headed Mahrez's shot off the line and Schmeichel saved before the end from Gestede as both teams searched in vain for a winner.