Craig Brown's men were worthy winners at a snowy Pittodrie and never looked back after John Sutton's opener after 29 minutes.
Lukas Jutkiewicz nodded home a second five minutes after the break before Sutton struck again three minutes later.
The toothless Dons rarely troubled the Well rearguard who kept their fourth successive clean sheet in the league.
Aberdeen named the same starting XI that defeated Hearts 3-0 in midweek with youngster Peter Pawlett again missing out with a knee injury, while Zander Diamond started on the bench.
The suspended Giles Coke missed out for the visitors who made three changes to the side that drew with Falkirk on Wednesday.
Striker Jutkiewicz was preferred to Jamie Murphy, while Marc Fitzpatrick and Steve Jennings were also given starting berths with Ross Forbes dropping to the bench.
The Steelmen created the first chance of the game after six minutes when Sutton blasted a left-footed volley from an acute angle wide of the target.
Charlie Mulgrew blasted a free kick off the Well wall from 30 yards a minute later before collecting the rebound and unleashing a powerful strike that John Ruddy palmed away.
Ruddy then thwarted Gary McDonald after nine minutes. McDonald was gifted an opportunity following slack play by Keith Lasley, who picked up the first booking three minutes later for a needless challenge on Richard Foster.
Langfield in the Aberdeen goal made a terrific save to claw away a Jim O'Brien strike from the edge of the area that looked destined for the top right corner after 18 minutes.
Derek Young, a goalscoring hero for the Dons in their previous two matches, almost put the ball in his own net when he sliced a Tom Hateley corner onto the crossbar.
The Motherwell pressure was mounting and the inevitable opener came after 29 minutes when O'Brien sped past Davide Grassi before unleashing a low shot that was parried by Langfield into the path of Sutton who had the easiest of finishes.
The Englishman should have doubled his side's advantage after 37 minutes when Jennings squared the ball into his path but from eight yards out but the former St Mirren striker failed to hit the target.
Darren Mackie was denied by the feet of Ruddy before the English keeper pulled off another smart save to tip over a deflected Richard Foster drive from 40 yards.
The Dons should have equalised on the stroke of half-time when Lee Miller nodded a Mulgrew free-kick into the path of McDonald but a combination of the far post and Ruddy kept the ball from hitting the back of the net.
Motherwell doubled their advantage five minutes after the restart when Hateley crossed for Sutton who headed the ball across goal for Jutkiewicz to nod home, despite the best efforts of Young to keep the ball from crossing the line.
And things went from bad to worse for Aberdeen three minutes later when Langfield could not hold Stephen Craig's header from a Hateley free-kick and Sutton was again on hand to bundle the ball home.
O'Brien was enjoying a fine game and almost got on his name on the scoresheet after 64 minutes with a darting run and shot that Langfield did well to keep out.
Substitute Chris Maguire, who had replaced Grassi, was booked for a late challenge on O'Brien as the home side's frustrations began to grow.
Fellow substitute Michael Paton shot wide before Mulgrew struck the defensive wall with another venomous free-kick as time ran out for the Dons.
The home support showed their frustrations at the full-time whistle as the jeers rang out around Pittodrie.