Rory Fallon snatched a draw for 10-man Swansea as both teams earned their first points in League One this season.
The Swans were a man down after just 16 minutes when Alan Tate was sent off for a wild two-footed lunge.
But they took a surprise lead on the stroke of half-time when Andy Robinson fired in a cracking shot from 18 yards.
Scunthorpe pressed hard and were ahead on 67 minutes when Bill Sharp added to Andy Crosby's penalty, but Fallon headed the equaliser 10 minutes later.
Scunthorpe: Murphy, Mulligan, Crosby, Foster, Ridley, Taylor, Hinds, Baraclough (Andrea Ferretti 88), Sparrow, Keogh, Sharp.
Subs Not Used: Byrne, MacKenzie, Williams, Lillis.
Goals: Crosby 49 pen, Sharp 67.
Swansea: Gueret, Amankwaah, Iriekpen, Monk (Austin 29), Williams, Robinson, Pratley, Tate, McLeod (Butler 67), Fallon, Knight (Trundle 45).
Subs Not Used: Oakes, Akinfenwa.
Sent Off: Tate (16).
Goals: Robinson 45, Fallon 78.
Ref: N Miller (Co Durham).