Roberts hit the clinching goal - his seventh of the campaign - to keep Huddersfield on course for a New Year tilt at the play-offs.
Hereford, who secured their first away win of the season at Colchester two weeks ago, did their best to thwart Huddersfield but in the end slumped to another defeat.
The Bulls kept Huddersfield at bay for long periods before centre-back Nathan Clarke broke the deadlock in the 70th minute. Seven minutes later Roberts sealed it and Clark had breathing space.
Hereford almost snatched a shock lead in the second minute when Robbie Williams headed off the line from Josh Gowling.
Then it was all one-way traffic as Huddersfield dominated but failed to find the finishing touch.
Bulls keeper Craig Samson tipped over a Robbie Williams header and then produced a superb save a minute later to deny Williams again.
Roberts had a couple of efforts but never got a clear enough sight of goal as the first half finished goalless.
After the break Hereford winger Lionel Ainsworth proved a livewire and was dangerous with his pace.
It was his cross which was almost turned into his own goal by Clarke and Andrew Williams escaped the Huddersfield defence but fired straight at Alex Smithies.
Ainsworth made a fast breakaway move and his stinging shot went just over. A Steve Guinan flick landed on the roof of the net and then Smithies palmed a shot over.
Hereford boss Graham Turner thought his side should have had a penalty in the 70th minute when Andy Butler upended Andrew Williams.
However, referee David Webb turned down the appeals and Town went down the other end and won a corner.
From that sub Danny Cadamarteri crossed, the ball was partially cleared by Richard Rose, and Clarke smashed home from close range.
Guinan then missed a great chance to level three minutes later and it was all over when Roberts pounced for the clinching goal.
He skipped through the Hereford defence, twice exchanging passes with Phil Jevons, and slotted into the bottom corner to leave boss Clark celebrating.