It was the Blades who dominated the opening half an hour as Scunthorpe struggled to get going.
Matty Done missed a golden chance to open the scoring when he popped up unmarked on the edge of the six-yard box but flashed a diving header wide of the far post.
Midfield man Louis Reed also went close with a 25-yard effort before Scunthorpe snatched a 37th-minute lead.
It was against the run of play when Neal Bishop netted with a close-range header after a free-kick had been turned back across goal by Niall Canavan.
But Sheffield were deservedly back on level terms on the stroke of half-time when full-back Kieron Freeman popped up in the box to force an angled shot into the far side of the net.
In a fiesty start to the second half Scunthorpe thought they were back in front when Blades goalkeeper Iain Turner fumbled an inswinging corner from Gary McSheffrey into his own net. However, their celebrations were cut short when referee Darren Handley blew for an infringement in a crowded box.
Both teams might have snatched all three points in the closing stages. Substitute Jason Holt twice went close for the visitors, while at the opposite end leading marksman Paddy Madden fluffed two good openings for Scunthorpe.