Goals from David Clarkson and Nicky Maynard sealed a deserved success for the Robins.
In a tepid encounter, the hosts took the lead in the 13th minute when Clarkson's inswinging cross found the back of the net.
Although City were able to control the tempo of the match, they failed to fashion many first-half chances.
However, Maynard struck after the interval to wrap up the points after converting from Martyn Woolford's corner.
Keith Millen's side moved 10 points clear of the npower Championship relegation zone, whilst Scunthorpe were left five points adrift of safety.
Both City and the Iron were unchanged from midweek victories over Watford and Sheffield United respectively.
After an opening in which neither side could impose their will on the clash, the hosts ended their goal drought at Ashton Gate in fortuitous circumstances.
Clarkson's curling left-wing cross evaded everyone in the area before the ball went in off the far post for City's first home goal since New Year's Day.
The hosts continued to push forward but, despite their dominance, they failed to fashion any meaningful opportunities, although the impressive Clarkson's ferocious 25-yard strike was magnificently beaten away by Scunthorpe keeper Josh Lillis.
The Iron had taken seven points from their last available nine - including coming back from two goals down to beat Sheffield United on Tuesday - so their poor first-half showing was unlikely to have impressed manager Ian Baraclough.
His mood was certainly not improved when Maynard doubled Bristol City's advantage four minutes after the interval.
Former Scunthorpe midfielder Woolford's bobbling corner was guided home by Maynard for his second goal in as many games.
The striker, making just his second start of the season since returning from a serious knee injury, was then put through on goal but after rounding Lillis, he could only fire over.
Abdisalam Ibrahim had Scunthorpe's first on-target effort of the day from just outside the area but the strike was comfortably caught by City goalkeeper David James.
Clarkson was denied by Lillis before Scunthorpe were, once again, almost undone by a Robins set-piece.
Liam Fontaine's flick-on from Woolford's corner was hacked off the line by Ben Gordon.
The Scunthorpe defender then spurned his side's best chance of the afternoon when his strike from 12 yards went inches wide of James' right-hand post.
Kalifa Cisse brought the ball forward from midfield before finding Maynard on the edge of the area and he twisted and turned past Michael Raynes before firing over.
It mattered little though as City had already sealed the three points.
Source: DSG